LeetCode

Languages

Earned Badges

Problem Solving

LeetCode Topics

Array

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0033-search-in-rotated-sorted-array	Medium
0035-search-insert-position	Easy
0153-find-minimum-in-rotated-sorted-array	Medium
0154-find-minimum-in-rotated-sorted-array-ii	Hard
0200-number-of-islands	Medium
0453-minimum-moves-to-equal-array-elements	Medium
0462-minimum-moves-to-equal-array-elements-ii	Medium
0835-image-overlap	Medium
0877-stone-game	Medium
1140-stone-game-ii	Medium
1260-shift-2d-grid	Easy
1288-remove-covered-intervals	Medium
1301-number-of-paths-with-max-score	Hard
1306-jump-game-iii	Medium
1331-rank-transform-of-an-array	Easy
1340-jump-game-v	Hard
1345-jump-game-iv	Hard
1385-find-the-distance-value-between-two-arrays	Easy
1386-cinema-seat-allocation	Medium
1406-stone-game-iii	Hard
1464-maximum-product-of-two-elements-in-an-array	Easy
1477-find-two-non-overlapping-sub-arrays-each-with-target-sum	Medium
1658-minimum-operations-to-reduce-x-to-zero	Medium
1665-minimum-initial-energy-to-finish-tasks	Hard
1674-minimum-moves-to-make-array-complementary	Medium
1732-find-the-highest-altitude	Easy
1752-check-if-array-is-sorted-and-rotated	Easy
1807-evaluate-the-bracket-pairs-of-a-string	Medium
1833-maximum-ice-cream-bars	Medium
1840-maximum-building-height	Hard
1846-maximum-element-after-decreasing-and-rearranging	Medium
1882-process-tasks-using-servers	Medium
1914-cyclically-rotating-a-grid	Medium
1967-number-of-strings-that-appear-as-substrings-in-word	Easy
1984-minimum-difference-between-highest-and-lowest-of-k-scores	Easy
2029-stone-game-ix	Medium
2089-find-target-indices-after-sorting-array	Easy
2091-removing-minimum-and-maximum-from-array	Medium
2126-destroying-asteroids	Medium
2144-minimum-cost-of-buying-candies-with-discount	Easy
2161-partition-array-according-to-given-pivot	Medium
2213-longest-substring-of-one-repeating-character	Hard
2267-check-if-there-is-a-valid-parentheses-string-path	Hard
2333-minimum-sum-of-squared-difference	Medium
2540-minimum-common-value	Easy
2553-separate-the-digits-in-an-array	Easy
2574-left-and-right-sum-differences	Easy
2657-find-the-prefix-common-array-of-two-arrays	Medium
2770-maximum-number-of-jumps-to-reach-the-last-index	Medium
2778-sum-of-squares-of-special-elements	Easy
2784-check-if-array-is-good	Easy
2812-find-the-safest-path-in-a-grid	Medium
2913-subarrays-distinct-element-sum-of-squares-i	Easy
2916-subarrays-distinct-element-sum-of-squares-ii	Hard
2996-smallest-missing-integer-greater-than-sequential-prefix-sum	Easy
3010-divide-an-array-into-subarrays-with-minimum-cost-i	Easy
3020-find-the-maximum-number-of-elements-in-subset	Medium
3043-find-the-length-of-the-longest-common-prefix	Medium
3069-distribute-elements-into-two-arrays-i	Easy
3093-longest-common-suffix-queries	Hard
3116-kth-smallest-amount-with-single-denomination-combination	Hard
3161-block-placement-queries	Hard
3286-find-a-safe-walk-through-a-grid	Medium
3300-minimum-element-after-replacement-with-digit-sum	Easy
3379-transformed-array	Easy
3471-find-the-largest-almost-missing-integer	Easy
3483-unique-3-digit-even-numbers	Easy
3501-maximize-active-section-with-trade-ii	Hard
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard
3524-find-x-value-of-array-i	Medium
3525-find-x-value-of-array-ii	Hard
3532-path-existence-queries-in-a-graph-i	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3550-smallest-index-with-digit-sum-equal-to-index	Easy
3551-minimum-swaps-to-sort-by-digit-sum	Medium
3559-number-of-ways-to-assign-edge-weights-ii	Hard
3568-minimum-moves-to-clean-the-classroom	Medium
3633-earliest-finish-time-for-land-and-water-rides-i	Easy
3635-earliest-finish-time-for-land-and-water-rides-ii	Medium
3689-maximum-total-subarray-value-i	Medium
3691-maximum-total-subarray-value-ii	Hard
3693-climbing-stairs-ii	Medium
3702-longest-subsequence-with-non-zero-bitwise-xor	Medium
3718-smallest-missing-multiple-of-k	Easy
3727-maximum-alternating-sum-of-squares	Medium
3731-find-missing-elements	Easy
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard
3838-weighted-word-mapping	Easy
3867-sum-of-gcd-of-formed-pairs	Medium
3875-construct-uniform-parity-array-i	Easy
3876-construct-uniform-parity-array-ii	Medium
3882-minimum-xor-path-in-a-grid	Medium
3903-smallest-stable-index-i	Easy
3904-smallest-stable-index-ii	Medium

Dynamic Programming

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0032-longest-valid-parentheses	Hard
0877-stone-game	Medium
0940-distinct-subsequences-ii	Hard
1140-stone-game-ii	Medium
1301-number-of-paths-with-max-score	Hard
1340-jump-game-v	Hard
1406-stone-game-iii	Hard
1477-find-two-non-overlapping-sub-arrays-each-with-target-sum	Medium
1510-stone-game-iv	Hard
1621-number-of-sets-of-k-non-overlapping-line-segments	Medium
1871-jump-game-vii	Medium
2267-check-if-there-is-a-valid-parentheses-string-path	Hard
2472-maximum-number-of-non-overlapping-palindrome-substrings	Hard
2770-maximum-number-of-jumps-to-reach-the-last-index	Medium
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard
3524-find-x-value-of-array-i	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3559-number-of-ways-to-assign-edge-weights-ii	Hard
3693-climbing-stairs-ii	Medium
3699-number-of-zigzag-arrays-i	Hard
3700-number-of-zigzag-arrays-ii	Hard
3751-total-waviness-of-numbers-in-range-i	Medium
3753-total-waviness-of-numbers-in-range-ii	Hard
3882-minimum-xor-path-in-a-grid	Medium

Simulation

Problem Name	Difficulty
0067-add-binary	Easy
1260-shift-2d-grid	Easy
1914-cyclically-rotating-a-grid	Medium
2161-partition-array-according-to-given-pivot	Medium
2553-separate-the-digits-in-an-array	Easy
3069-distribute-elements-into-two-arrays-i	Easy
3379-transformed-array	Easy
3498-reverse-degree-of-a-string	Easy
3612-process-string-with-special-operations-i	Medium
3838-weighted-word-mapping	Easy
3867-sum-of-gcd-of-formed-pairs	Medium

Matrix

Problem Name	Difficulty
0200-number-of-islands	Medium
0835-image-overlap	Medium
1260-shift-2d-grid	Easy
1301-number-of-paths-with-max-score	Hard
1914-cyclically-rotating-a-grid	Medium
2267-check-if-there-is-a-valid-parentheses-string-path	Hard
2812-find-the-safest-path-in-a-grid	Medium
3286-find-a-safe-walk-through-a-grid	Medium
3568-minimum-moves-to-clean-the-classroom	Medium
3882-minimum-xor-path-in-a-grid	Medium

Shell

Problem Name	Difficulty
0194-transpose-file	Medium

Greedy

Problem Name	Difficulty
0921-minimum-add-to-make-parentheses-valid	Medium
1386-cinema-seat-allocation	Medium
1520-maximum-number-of-non-overlapping-substrings	Hard
1665-minimum-initial-energy-to-finish-tasks	Hard
1833-maximum-ice-cream-bars	Medium
1846-maximum-element-after-decreasing-and-rearranging	Medium
1927-sum-game	Medium
2029-stone-game-ix	Medium
2091-removing-minimum-and-maximum-from-array	Medium
2126-destroying-asteroids	Medium
2144-minimum-cost-of-buying-candies-with-discount	Easy
2333-minimum-sum-of-squared-difference	Medium
2472-maximum-number-of-non-overlapping-palindrome-substrings	Hard
3014-minimum-number-of-pushes-to-type-word-i	Easy
3016-minimum-number-of-pushes-to-type-word-ii	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3633-earliest-finish-time-for-land-and-water-rides-i	Easy
3635-earliest-finish-time-for-land-and-water-rides-ii	Medium
3689-maximum-total-subarray-value-i	Medium
3691-maximum-total-subarray-value-ii	Hard
3720-lexicographically-smallest-permutation-greater-than-target	Medium
3727-maximum-alternating-sum-of-squares	Medium

Sorting

Problem Name	Difficulty
0462-minimum-moves-to-equal-array-elements-ii	Medium
1096-brace-expansion-ii	Hard
1288-remove-covered-intervals	Medium
1331-rank-transform-of-an-array	Easy
1340-jump-game-v	Hard
1385-find-the-distance-value-between-two-arrays	Easy
1464-maximum-product-of-two-elements-in-an-array	Easy
1520-maximum-number-of-non-overlapping-substrings	Hard
1665-minimum-initial-energy-to-finish-tasks	Hard
1833-maximum-ice-cream-bars	Medium
1840-maximum-building-height	Hard
1846-maximum-element-after-decreasing-and-rearranging	Medium
1984-minimum-difference-between-highest-and-lowest-of-k-scores	Easy
2089-find-target-indices-after-sorting-array	Easy
2126-destroying-asteroids	Medium
2144-minimum-cost-of-buying-candies-with-discount	Easy
2333-minimum-sum-of-squared-difference	Medium
2784-check-if-array-is-good	Easy
2996-smallest-missing-integer-greater-than-sequential-prefix-sum	Easy
3010-divide-an-array-into-subarrays-with-minimum-cost-i	Easy
3016-minimum-number-of-pushes-to-type-word-ii	Medium
3517-smallest-palindromic-rearrangement-i	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3551-minimum-swaps-to-sort-by-digit-sum	Medium
3633-earliest-finish-time-for-land-and-water-rides-i	Easy
3635-earliest-finish-time-for-land-and-water-rides-ii	Medium
3727-maximum-alternating-sum-of-squares	Medium
3731-find-missing-elements	Easy
3867-sum-of-gcd-of-formed-pairs	Medium

Hash Table

Problem Name	Difficulty
0013-roman-to-integer	Easy
1096-brace-expansion-ii	Hard
1189-maximum-number-of-balloons	Easy
1331-rank-transform-of-an-array	Easy
1345-jump-game-iv	Hard
1358-number-of-substrings-containing-all-three-characters	Medium
1386-cinema-seat-allocation	Medium
1477-find-two-non-overlapping-sub-arrays-each-with-target-sum	Medium
1520-maximum-number-of-non-overlapping-substrings	Hard
1658-minimum-operations-to-reduce-x-to-zero	Medium
1674-minimum-moves-to-make-array-complementary	Medium
1807-evaluate-the-bracket-pairs-of-a-string	Medium
2540-minimum-common-value	Easy
2657-find-the-prefix-common-array-of-two-arrays	Medium
2784-check-if-array-is-good	Easy
2913-subarrays-distinct-element-sum-of-squares-i	Easy
2916-subarrays-distinct-element-sum-of-squares-ii	Hard
2996-smallest-missing-integer-greater-than-sequential-prefix-sum	Easy
3016-minimum-number-of-pushes-to-type-word-ii	Medium
3020-find-the-maximum-number-of-elements-in-subset	Medium
3043-find-the-length-of-the-longest-common-prefix	Medium
3090-maximum-length-substring-with-two-occurrences	Easy
3120-count-the-number-of-special-characters-i	Easy
3121-count-the-number-of-special-characters-ii	Medium
3471-find-the-largest-almost-missing-integer	Easy
3483-unique-3-digit-even-numbers	Easy
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard
3532-path-existence-queries-in-a-graph-i	Medium
3551-minimum-swaps-to-sort-by-digit-sum	Medium
3568-minimum-moves-to-clean-the-classroom	Medium
3718-smallest-missing-multiple-of-k	Easy
3720-lexicographically-smallest-permutation-greater-than-target	Medium
3731-find-missing-elements	Easy
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard

Prefix Sum

Problem Name	Difficulty
1140-stone-game-ii	Medium
1621-number-of-sets-of-k-non-overlapping-line-segments	Medium
1658-minimum-operations-to-reduce-x-to-zero	Medium
1674-minimum-moves-to-make-array-complementary	Medium
1732-find-the-highest-altitude	Easy
1871-jump-game-vii	Medium
2574-left-and-right-sum-differences	Easy
3699-number-of-zigzag-arrays-i	Hard
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard
3903-smallest-stable-index-i	Easy
3904-smallest-stable-index-ii	Medium

Binary Search

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0033-search-in-rotated-sorted-array	Medium
0035-search-insert-position	Easy
0153-find-minimum-in-rotated-sorted-array	Medium
0154-find-minimum-in-rotated-sorted-array-ii	Hard
1385-find-the-distance-value-between-two-arrays	Easy
1477-find-two-non-overlapping-sub-arrays-each-with-target-sum	Medium
1658-minimum-operations-to-reduce-x-to-zero	Medium
2089-find-target-indices-after-sorting-array	Easy
2333-minimum-sum-of-squared-difference	Medium
2540-minimum-common-value	Easy
2812-find-the-safest-path-in-a-grid	Medium
3116-kth-smallest-amount-with-single-denomination-combination	Hard
3161-block-placement-queries	Hard
3501-maximize-active-section-with-trade-ii	Hard
3532-path-existence-queries-in-a-graph-i	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3633-earliest-finish-time-for-land-and-water-rides-i	Easy
3635-earliest-finish-time-for-land-and-water-rides-ii	Medium

Divide and Conquer

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0190-reverse-bits	Easy
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard

Depth-First Search

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0098-validate-binary-search-tree	Medium
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy
0200-number-of-islands	Medium
0226-invert-binary-tree	Easy
0257-binary-tree-paths	Easy
1306-jump-game-iii	Medium
2265-count-nodes-equal-to-average-of-subtree	Medium
2331-evaluate-boolean-binary-tree	Easy
2492-minimum-score-of-a-path-between-two-cities	Medium
2685-count-the-number-of-complete-components	Medium
3558-number-of-ways-to-assign-edge-weights-i	Medium
3559-number-of-ways-to-assign-edge-weights-ii	Hard

Breadth-First Search

Problem Name	Difficulty
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0200-number-of-islands	Medium
0226-invert-binary-tree	Easy
0301-remove-invalid-parentheses	Hard
1096-brace-expansion-ii	Hard
1306-jump-game-iii	Medium
1345-jump-game-iv	Hard
2492-minimum-score-of-a-path-between-two-cities	Medium
2685-count-the-number-of-complete-components	Medium
2812-find-the-safest-path-in-a-grid	Medium
3286-find-a-safe-walk-through-a-grid	Medium
3568-minimum-moves-to-clean-the-classroom	Medium

Two Pointers

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
1385-find-the-distance-value-between-two-arrays	Easy
2095-delete-the-middle-node-of-a-linked-list	Medium
2130-maximum-twin-sum-of-a-linked-list	Medium
2161-partition-array-according-to-given-pivot	Medium
2472-maximum-number-of-non-overlapping-palindrome-substrings	Hard
2540-minimum-common-value	Easy
3534-path-existence-queries-in-a-graph-ii	Hard
3633-earliest-finish-time-for-land-and-water-rides-i	Easy
3635-earliest-finish-time-for-land-and-water-rides-ii	Medium
3867-sum-of-gcd-of-formed-pairs	Medium

Bit Manipulation

Problem Name	Difficulty
0067-add-binary	Easy
0190-reverse-bits	Easy
0401-binary-watch	Easy
0693-binary-number-with-alternating-bits	Easy
1386-cinema-seat-allocation	Medium
2657-find-the-prefix-common-array-of-two-arrays	Medium
3116-kth-smallest-amount-with-single-denomination-combination	Hard
3534-path-existence-queries-in-a-graph-ii	Hard
3559-number-of-ways-to-assign-edge-weights-ii	Hard
3568-minimum-moves-to-clean-the-classroom	Medium
3702-longest-subsequence-with-non-zero-bitwise-xor	Medium
3882-minimum-xor-path-in-a-grid	Medium

String

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0006-zigzag-conversion	Medium
0013-roman-to-integer	Easy
0020-valid-parentheses	Easy
0032-longest-valid-parentheses	Hard
0067-add-binary	Easy
0257-binary-tree-paths	Easy
0301-remove-invalid-parentheses	Hard
0856-score-of-parentheses	Medium
0921-minimum-add-to-make-parentheses-valid	Medium
0940-distinct-subsequences-ii	Hard
1021-remove-outermost-parentheses	Easy
1096-brace-expansion-ii	Hard
1189-maximum-number-of-balloons	Easy
1358-number-of-substrings-containing-all-three-characters	Medium
1520-maximum-number-of-non-overlapping-substrings	Hard
1614-maximum-nesting-depth-of-the-parentheses	Easy
1758-minimum-changes-to-make-alternating-binary-string	Easy
1784-check-if-binary-string-has-at-most-one-segment-of-ones	Easy
1807-evaluate-the-bracket-pairs-of-a-string	Medium
1871-jump-game-vii	Medium
1927-sum-game	Medium
1967-number-of-strings-that-appear-as-substrings-in-word	Easy
2213-longest-substring-of-one-repeating-character	Hard
2409-count-days-spent-together	Easy
2472-maximum-number-of-non-overlapping-palindrome-substrings	Hard
2904-shortest-and-lexicographically-smallest-beautiful-string	Medium
3014-minimum-number-of-pushes-to-type-word-i	Easy
3016-minimum-number-of-pushes-to-type-word-ii	Medium
3043-find-the-length-of-the-longest-common-prefix	Medium
3090-maximum-length-substring-with-two-occurrences	Easy
3093-longest-common-suffix-queries	Hard
3120-count-the-number-of-special-characters-i	Easy
3121-count-the-number-of-special-characters-ii	Medium
3498-reverse-degree-of-a-string	Easy
3499-maximize-active-section-with-trade-i	Medium
3501-maximize-active-section-with-trade-ii	Hard
3517-smallest-palindromic-rearrangement-i	Medium
3612-process-string-with-special-operations-i	Medium
3720-lexicographically-smallest-permutation-greater-than-target	Medium
3838-weighted-word-mapping	Easy
3970-shortest-path-with-at-most-k-consecutive-identical-characters	Medium

Trie

Problem Name	Difficulty
3043-find-the-length-of-the-longest-common-prefix	Medium
3093-longest-common-suffix-queries	Hard

Sliding Window

Problem Name	Difficulty
1358-number-of-substrings-containing-all-three-characters	Medium
1477-find-two-non-overlapping-sub-arrays-each-with-target-sum	Medium
1658-minimum-operations-to-reduce-x-to-zero	Medium
1871-jump-game-vii	Medium
1984-minimum-difference-between-highest-and-lowest-of-k-scores	Easy
2904-shortest-and-lexicographically-smallest-beautiful-string	Medium
3090-maximum-length-substring-with-two-occurrences	Easy
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard

Math

Problem Name	Difficulty
0007-reverse-integer	Medium
0013-roman-to-integer	Easy
0067-add-binary	Easy
0453-minimum-moves-to-equal-array-elements	Medium
0462-minimum-moves-to-equal-array-elements-ii	Medium
0836-rectangle-overlap	Easy
0877-stone-game	Medium
1140-stone-game-ii	Medium
1401-circle-and-rectangle-overlapping	Medium
1406-stone-game-iii	Hard
1510-stone-game-iv	Hard
1621-number-of-sets-of-k-non-overlapping-line-segments	Medium
1840-maximum-building-height	Hard
1927-sum-game	Medium
2029-stone-game-ix	Medium
2409-count-days-spent-together	Easy
3014-minimum-number-of-pushes-to-type-word-i	Easy
3116-kth-smallest-amount-with-single-denomination-combination	Hard
3300-minimum-element-after-replacement-with-digit-sum	Easy
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard
3524-find-x-value-of-array-i	Medium
3525-find-x-value-of-array-ii	Hard
3550-smallest-index-with-digit-sum-equal-to-index	Easy
3558-number-of-ways-to-assign-edge-weights-i	Medium
3559-number-of-ways-to-assign-edge-weights-ii	Hard
3622-check-divisibility-by-digit-sum-and-product	Easy
3658-gcd-of-odd-and-even-sums	Easy
3700-number-of-zigzag-arrays-ii	Hard
3751-total-waviness-of-numbers-in-range-i	Medium
3753-total-waviness-of-numbers-in-range-ii	Hard
3754-concatenate-non-zero-digits-and-multiply-by-sum-i	Easy
3867-sum-of-gcd-of-formed-pairs	Medium
3870-count-commas-in-range	Easy
3871-count-commas-in-range-ii	Medium
3875-construct-uniform-parity-array-i	Easy
3876-construct-uniform-parity-array-ii	Medium

Linked List

Problem Name	Difficulty
0021-merge-two-sorted-lists	Easy
2058-find-the-minimum-and-maximum-number-of-nodes-between-critical-points	Medium
2095-delete-the-middle-node-of-a-linked-list	Medium
2130-maximum-twin-sum-of-a-linked-list	Medium

Recursion

Problem Name	Difficulty
0021-merge-two-sorted-lists	Easy
3483-unique-3-digit-even-numbers	Easy

Binary Indexed Tree

Problem Name	Difficulty
2913-subarrays-distinct-element-sum-of-squares-i	Easy
2916-subarrays-distinct-element-sum-of-squares-ii	Hard
3161-block-placement-queries	Hard

Segment Tree

Problem Name	Difficulty
2213-longest-substring-of-one-repeating-character	Hard
2913-subarrays-distinct-element-sum-of-squares-i	Easy
2916-subarrays-distinct-element-sum-of-squares-ii	Hard
3161-block-placement-queries	Hard
3501-maximize-active-section-with-trade-ii	Hard
3525-find-x-value-of-array-ii	Hard
3691-maximum-total-subarray-value-ii	Hard
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard

Enumeration

Problem Name	Difficulty
1291-sequential-digits	Medium
2778-sum-of-squares-of-special-elements	Easy
3010-divide-an-array-into-subarrays-with-minimum-cost-i	Easy
3020-find-the-maximum-number-of-elements-in-subset	Medium
3483-unique-3-digit-even-numbers	Easy
3499-maximize-active-section-with-trade-i	Medium
3720-lexicographically-smallest-permutation-greater-than-target	Medium
3751-total-waviness-of-numbers-in-range-i	Medium

Heap (Priority Queue)

Problem Name	Difficulty
1464-maximum-product-of-two-elements-in-an-array	Easy
1882-process-tasks-using-servers	Medium
2333-minimum-sum-of-squared-difference	Medium
2812-find-the-safest-path-in-a-grid	Medium
3286-find-a-safe-walk-through-a-grid	Medium
3505-minimum-operations-to-make-elements-within-k-subarrays-equal	Hard
3691-maximum-total-subarray-value-ii	Hard
3970-shortest-path-with-at-most-k-consecutive-identical-characters	Medium

Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0098-validate-binary-search-tree	Medium
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy
0226-invert-binary-tree	Easy
0257-binary-tree-paths	Easy
2265-count-nodes-equal-to-average-of-subtree	Medium
2331-evaluate-boolean-binary-tree	Easy
3558-number-of-ways-to-assign-edge-weights-i	Medium
3559-number-of-ways-to-assign-edge-weights-ii	Hard

Binary Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0098-validate-binary-search-tree	Medium
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy
0226-invert-binary-tree	Easy
0257-binary-tree-paths	Easy
2265-count-nodes-equal-to-average-of-subtree	Medium
2331-evaluate-boolean-binary-tree	Easy

Union-Find

Problem Name	Difficulty
0200-number-of-islands	Medium
2492-minimum-score-of-a-path-between-two-cities	Medium
2685-count-the-number-of-complete-components	Medium
2812-find-the-safest-path-in-a-grid	Medium
3532-path-existence-queries-in-a-graph-i	Medium

Stack

Problem Name	Difficulty
0020-valid-parentheses	Easy
0032-longest-valid-parentheses	Hard
0094-binary-tree-inorder-traversal	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy
0856-score-of-parentheses	Medium
0921-minimum-add-to-make-parentheses-valid	Medium
1021-remove-outermost-parentheses	Easy
1096-brace-expansion-ii	Hard
1614-maximum-nesting-depth-of-the-parentheses	Easy
2130-maximum-twin-sum-of-a-linked-list	Medium

Backtracking

Problem Name	Difficulty
0257-binary-tree-paths	Easy
0301-remove-invalid-parentheses	Hard
0401-binary-watch	Easy
1096-brace-expansion-ii	Hard

Counting Sort

Problem Name	Difficulty
1189-maximum-number-of-balloons	Easy
1833-maximum-ice-cream-bars	Medium
2029-stone-game-ix	Medium
3016-minimum-number-of-pushes-to-type-word-ii	Medium
3517-smallest-palindromic-rearrangement-i	Medium
3720-lexicographically-smallest-permutation-greater-than-target	Medium
3737-count-subarrays-with-majority-element-i	Medium

Merge Sort

Problem Name	Difficulty
3737-count-subarrays-with-majority-element-i	Medium
3739-count-subarrays-with-majority-element-ii	Hard

Graph Theory

Problem Name	Difficulty
2492-minimum-score-of-a-path-between-two-cities	Medium
2685-count-the-number-of-complete-components	Medium
3286-find-a-safe-walk-through-a-grid	Medium
3532-path-existence-queries-in-a-graph-i	Medium
3534-path-existence-queries-in-a-graph-ii	Hard
3970-shortest-path-with-at-most-k-consecutive-identical-characters	Medium

Shortest Path

Problem Name	Difficulty
3286-find-a-safe-walk-through-a-grid	Medium
3970-shortest-path-with-at-most-k-consecutive-identical-characters	Medium

Number Theory

Problem Name	Difficulty
3116-kth-smallest-amount-with-single-denomination-combination	Hard
3658-gcd-of-odd-and-even-sums	Easy
3867-sum-of-gcd-of-formed-pairs	Medium

Game Theory

Problem Name	Difficulty
0877-stone-game	Medium
1140-stone-game-ii	Medium
1406-stone-game-iii	Hard
1510-stone-game-iv	Hard
1927-sum-game	Medium
2029-stone-game-ix	Medium

Minimax

Problem Name	Difficulty
1140-stone-game-ii	Medium
1406-stone-game-iii	Hard
1510-stone-game-iv	Hard
2029-stone-game-ix	Medium

Zero-Sum Game

Problem Name	Difficulty
1140-stone-game-ii	Medium
1406-stone-game-iii	Hard
1510-stone-game-iv	Hard
2029-stone-game-ix	Medium

Nim Game

Problem Name	Difficulty
1510-stone-game-iv	Hard
2029-stone-game-ix	Medium

Sprague–Grundy Theorem

Problem Name	Difficulty
1510-stone-game-iv	Hard

Ordered Set

Problem Name	Difficulty
2213-longest-substring-of-one-repeating-character	Hard

Combinatorics

Problem Name	Difficulty
1621-number-of-sets-of-k-non-overlapping-line-segments	Medium
3116-kth-smallest-amount-with-single-denomination-combination	Hard

Binary Search Tree

Problem Name	Difficulty
0098-validate-binary-search-tree	Medium

Geometry

Problem Name	Difficulty
0836-rectangle-overlap	Easy
1401-circle-and-rectangle-overlapping	Medium

Manacher

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium

Bracket Sequences

Problem Name	Difficulty
0020-valid-parentheses	Easy
0032-longest-valid-parentheses	Hard
0856-score-of-parentheses	Medium
0921-minimum-add-to-make-parentheses-valid	Medium
1021-remove-outermost-parentheses	Easy
1614-maximum-nesting-depth-of-the-parentheses	Easy
2267-check-if-there-is-a-valid-parentheses-string-path	Hard