18. 4Sum

emd_challenge/challenge_10.py

@@ -0,0 +1,69 @@
+"""
+54. Spiral Matrix
+
+Given an m x n matrix, return all elements of the matrix in spiral order.
+
+Example 1:
+Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
+Output: [1,2,3,6,9,8,7,4,5]
+
+Example 2:
+Input: matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
+Output: [1,2,3,4,8,12,11,10,9,5,6,7]
+"""
+
+from typing import List
+
+"""
+[
+    [1,2,3],
+    [4,5,6],
+    [7,8,9]
+]
+
+00,01,02
+10,11,12
+20,21,22
+
+"""
+
+
+def spiralOrder(matrix: List[List[int]]) -> List[int]:
+    if not matrix or not matrix[0]:
+        return []
+    n = len(matrix)
+    m = len(matrix[0])
+    result = []
+    top, bottom = 0, n - 1
+    left, right = 0, m - 1
+
+    """
+    [
+        [1,2,3],
+        [4,5,6],
+        [7,8,9]
+    ]
+
+    """
+
+    # left -> right -> bottom -> left -> top
+    while top <= bottom and left <= right:
+        for i in range(left, right + 1):
+            result.append(matrix[top][i])
+        top += 1
+
+        for i in range(top, bottom + 1):
+            result.append(matrix[i][right])
+        right -= 1
+
+        if top <= bottom:
+            for i in range(right, left - 1, -1):
+                result.append(matrix[bottom][i])
+            bottom -= 1
+
+        if left <= right:
+            for i in range(bottom, top - 1, -1):
+                result.append(matrix[i][left])
+            left += 1
+
+    return result

emd_challenge/challenge_9.py

@@ -0,0 +1,70 @@
+"""
+18. 4Sum
+
+Given an array nums of n integers, return an array of all the unique
+quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:
+0 <= a, b, c, d < n
+a, b, c, and d are distinct.
+nums[a] + nums[b] + nums[c] + nums[d] == target
+You may return the answer in any order.
+
+Example 1:
+Input: nums = [1,0,-1,0,-2,2], target = 0
+Output: [[-2,-1,1,2],[-2,0,0,2],[-1,0,0,1]]
+
+Example 2:
+Input: nums = [2,2,2,2,2], target = 8
+Output: [[2,2,2,2]]
+
+Constraints:
+1 <= nums.length <= 200
+-109 <= nums[i] <= 109
+-109 <= target <= 109
+"""
+
+from typing import List
+
+
+def fourSum(nums: List[int], target: int) -> List[List[int]]:
+
+    n = len(nums)
+    result = []
+    hash_set = set()
+
+    nums.sort()
+    # [1,0,-1,0,-2,2]
+    # [-2, -1, 0, 0, 1, 2]
+    for i in range(n - 3):
+        for j in range(i + 1, n - 2):
+            left = j + 1
+            right = n - 1
+            while left < right:
+                four_sum = nums[i] + nums[j] + nums[left] + nums[right]
+
+                if four_sum == target:
+
+                    sort = (nums[i], nums[j], nums[left], nums[right])
+                    left += 1
+                    right -= 1
+
+                    result.append(sort)
+                elif four_sum > target:
+                    right -= 1
+                else:
+                    left += 1
+
+    return result
+
+    # n = len(nums)
+    # result = []
+
+    # for i in range(n - 3):
+    #     for j in range(i + 1, n - 2):
+    #         for k in range(j + 1, n - 1):
+    #             for x in range(k + 1, n):
+    #                 if nums[i] + nums[j] + nums[k] + nums[x] == target:
+    #                     sort = sorted([nums[i], nums[j], nums[k], nums[x]])
+    #                     if sort not in result:
+    #                         result.append(sort)
+
+    # return result

main.py

@@ -17,11 +17,13 @@
 from arr.trapping_rain_water import trap_app
 from arr.two_sum_11 import two_sum_brute, two_sum_two_pointer
 from emd_challenge.challenge_1 import longestCommonPrefix
+from emd_challenge.challenge_10 import spiralOrder
 from emd_challenge.challenge_2 import missingInteger
 from emd_challenge.challenge_3 import removeDuplicates
 from emd_challenge.challenge_5 import lengthOfLastWord
 from emd_challenge.challenge_6 import moveZeroes
 from emd_challenge.challenge_8 import addBinary
+from emd_challenge.challenge_9 import fourSum
 from stack.asteroid_collision_735 import asteroidCollision
 from stack.daily_temparature_739 import dailyTemperatures_2
 from stack.first_greater_element_2 import nextGreaterElements
@@ -44,7 +46,7 @@
 
 # sortColors_app2([2, 0, 2, 1, 1, 0])
 
-ans = addBinary(a="11", b="1")
+ans = spiralOrder([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
 print(ans)
 
 # stockSpanner = StockSpanner2()