카카오 2024 겨울

WEEK10/프로그래머스_가장많이받은선물/liv.swift

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+// 프로그래머스 - 가장 많이 받은 선물
+
+import Foundation
+
+func solution(_ friends: [String], _ gifts: [String]) -> Int {
+    var giftScore = [Int](repeating: 0, count: friends.count)
+    var history = [[String: Int]](repeating: [:], count: friends.count)
+    var next = [Int](repeating: 0, count: friends.count)
+
+    for gift in gifts {
+        let line = gift.split(separator: " ").map { String($0) }
+        let sender = friends.firstIndex(of: line[0])!
+        let receiver = friends.firstIndex(of: line[1])!
+
+        giftScore[sender] += 1
+        giftScore[receiver] -= 1
+
+        history[sender][line[1], default: 0] += 1
+    }
+
+    for (index, name) in friends.enumerated() {
+        var friend = index + 1
+        while friend < friends.count {
+            let friendName = friends[friend]
+            let fromMe = history[index][friendName] ?? 0
+            let fromFriend = history[friend][name] ?? 0
+
+            if fromMe > fromFriend { next[index] += 1 }
+            else if fromMe < fromFriend { next[friend] += 1 }
+            else {
+                let myScore = giftScore[index]
+                let friendScore = giftScore[friend]
+                if myScore > friendScore { next[index] += 1 }
+                else if myScore < friendScore { next[friend] += 1 }
+            }
+
+            friend += 1
+        }
+    }
+
+    return next.max() ?? 0
+}

WEEK10/프로그래머스_도넛과막대그래프/liv.swift

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+// 프로그래머스 - 도넛과 막대 그래프
+
+import Foundation
+
+func solution(_ edges: [[Int]]) -> [Int] {
+    var donut = 0; var stick = 0; var eight = 0
+    var answer = 0
+
+    var count = 0
+    edges.forEach { count = max(count, max($0[0], $0[1])) }
+
+    var inTable = [Int](repeating: 0, count: count + 1)
+    var outTable = [Set<Int>](repeating: [], count: count + 1)
+    edges.forEach { edge in
+        outTable[edge[0]].insert(edge[1])
+        inTable[edge[1]] += 1
+    }
+
+    var startItems = Set<Int>()
+    for (number, targets) in outTable.enumerated() 
+    where targets.count >= 2 && inTable[number] == 0 {
+        answer = number
+        startItems = outTable[answer]
+        break
+    }
+
+    for item in startItems {
+        var visited = Set<Int>()
+        var current = item
+
+        while true {
+            if visited.contains(current) { donut += 1; break }
+
+            let nextItems = outTable[current]
+            visited.insert(current)
+
+            if nextItems.isEmpty { stick += 1; break }
+
+            if nextItems.count == 2 { eight += 1; break }
+
+            current = nextItems.first!
+        }
+    }
+
+    return [answer, donut, stick, eight]
+}

WEEK10/프로그래머스_산모양타일링/liv.swift

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+// 프로그래머스 - 산 모양 타일링
+
+import Foundation
+
+func solution(_ n: Int, _ tops: [Int]) -> Int {
+    var dp1 = [Int](repeating: 0, count: n+1)
+    var dp2 = [Int](repeating: 1, count: n+1)
+
+    for index in 1...n {
+        dp1[index] = (dp1[index - 1] + dp2[index - 1]) % 10007
+        if tops[index - 1] == 1 {
+            dp2[index] = (dp1[index - 1] * 2 + dp2[index - 1] * 3) % 10007
+        }
+        else {
+            dp2[index] = (dp1[index - 1] + dp2[index - 1] * 2) % 10007
+        }
+    }
+    return (dp1[n] + dp2[n]) % 10007
+}