[전현수] - 치즈, 가장 긴 증가하는 부분 수열 4, 내리막 길, 삼각 달팽이

src/main/kotlin/hyunsoo/64week/가장 긴 증가하는 부분 수열 4.kt

@@ -0,0 +1,65 @@
+package hyunsoo.`64week`
+
+/**
+ *
+ * <문제>
+ * [가장 긴 증가하는 부분 수열 4](https://www.acmicpc.net/problem/14002)
+ *
+ * - 아이디어
+ *
+ * - 트러블 슈팅
+ *
+ */
+class `전현수_가장_긴_증가하는_부분_수열_4` {
+
+    fun solution() {
+        val n = readln().toInt()
+        val array = readln().split(" ").map { it.toInt() }
+        val dp = Array(n) {
+            intArrayOf()
+        }
+
+        var answerIndex = 0
+        var maxLength = 0
+
+        dp[0] = intArrayOf(array[0])
+        for (cur in 0 until n) {
+
+            dp[cur] = intArrayOf(array[cur])
+
+            var lisIndex = cur
+            var lisSize = 1
+
+            for (target in 0 until cur) {
+
+                // 앞에 수열의 마지막 값보다 내가 더 크고
+                if (array[target] < array[cur]) {
+                    // 갱신할 부분 수열의 길이가 더 길 때
+                    if (lisSize < dp[target].size + 1) {
+                        lisSize = dp[target].size
+                        lisIndex = target
+                    }
+                }
+            }
+
+            if (lisIndex != cur) {
+                dp[cur] = dp[lisIndex] + array[cur]
+            }
+
+            if (maxLength < dp[cur].size) {
+                answerIndex = cur
+                maxLength = dp[cur].size
+            }
+        }
+
+        println(maxLength)
+        dp[answerIndex].forEach {
+            print("$it ")
+        }
+
+    }
+}
+
+fun main() {
+    전현수_가장_긴_증가하는_부분_수열_4().solution()
+}

src/main/kotlin/hyunsoo/64week/내리막 길.kt

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+package hyunsoo.`64week`
+
+/**
+ *
+ * <문제>
+ * [내리막 길](https://www.acmicpc.net/problem/1520)
+ *
+ * - 아이디어
+ *
+ * - 트러블 슈팅
+ *
+ */
+class `전현수_내리막_길` {
+
+    private data class Position(val x: Int, val y: Int)
+
+    private val dirs = listOf(
+        Position(0, 1),
+        Position(0, -1),
+        Position(1, 0),
+        Position(-1, 0),
+    )
+
+    private var n = 0
+    private var m = 0
+    private val board = mutableListOf<MutableList<Int>>()
+    private lateinit var dp: Array<IntArray>
+
+    fun solution() {
+        init()
+        dfs(Position(0, 0))
+        println(dp[0][0])
+    }
+
+    private fun init() {
+        readln().split(" ").map { it.toInt() }
+            .apply {
+                n = this.first()
+                m = this.last()
+            }
+
+        dp = Array(n) {
+            IntArray(m) { -1 }
+        }
+
+        repeat(n) {
+            board.add(readln().split(" ").map { it.toInt() } as MutableList)
+        }
+    }
+
+    private fun dfs(pos: Position): Int {
+
+        // 목적지라면
+        if (pos.x == n - 1 && pos.y == m - 1) {
+            return 1
+        }
+
+        // 이미 탐색한 곳이라면
+        if (dp[pos.x][pos.y] != -1) return dp[pos.x][pos.y]
+
+        dp[pos.x][pos.y] = 0
+        dirs.forEach {
+            val nx = pos.x + it.x
+            val ny = pos.y + it.y
+
+            if (nx !in 0 until n ||
+                ny !in 0 until m ||
+                board[pos.x][pos.y] <= board[nx][ny]
+            ) return@forEach
+
+            dp[pos.x][pos.y] += dfs(Position(nx, ny))
+        }
+
+        return dp[pos.x][pos.y]
+    }
+}
+
+fun main() {
+    전현수_내리막_길().solution()
+}

src/main/kotlin/hyunsoo/64week/삼각 달팽이.kt

@@ -0,0 +1,71 @@
+package hyunsoo.`64week`
+
+/**
+ *
+ * <문제>
+ * [삼각 달팽이](https://school.programmers.co.kr/learn/courses/30/lessons/68645)
+ *
+ * - 아이디어
+ *
+ * - 트러블 슈팅
+ *
+ */
+class `전현수_삼각_달팽이` {
+
+    private data class Position(val x: Int, val y: Int)
+
+    private val dirs = listOf(
+        Position(1, 0),
+        Position(0, 1),
+        Position(-1, -1),
+    )
+
+    fun solution(n: Int): List<Int> {
+
+        val array = Array(n) {
+            IntArray(n) { 0 }
+        }
+
+        var x = -1
+        var y = 0
+        var dirIndex = 0
+        var curNum = 1
+
+        // 방향 전환할 때 까지 움직여야할 횟수
+        var changeNumCnt = n
+        // 움직인 횟수
+        var moveCnt = 0
+
+        while (curNum <= n.getCnt()) {
+
+            val curDir = dirs[dirIndex]
+            x += curDir.x
+            y += curDir.y
+            array[x][y] = curNum++
+            moveCnt++
+
+            if (moveCnt == changeNumCnt) {
+                dirIndex++
+                dirIndex %= 3
+                moveCnt = 0
+                changeNumCnt--
+            }
+
+        }
+        return array.map { row ->
+            row.filter { it != 0 }
+        }.flatten()
+    }
+
+    private fun Int.getCnt(): Int {
+        var target = 0
+        for (i in 1..this) target += i
+        return target
+    }
+}
+
+fun main() {
+    전현수_삼각_달팽이().solution(6).apply {
+        println(this)
+    }
+}

src/main/kotlin/hyunsoo/64week/치즈.kt

@@ -0,0 +1,117 @@
+package hyunsoo.`64week`
+
+import java.util.*
+
+/**
+ *
+ * <문제>
+ * [치즈](https://www.acmicpc.net/problem/2638)
+ *
+ * - 아이디어
+ *
+ * - 트러블 슈팅
+ *
+ */
+class `전현수_치즈` {
+
+    private data class Position(val x: Int, val y: Int)
+
+    private val board = mutableListOf<MutableList<Int>>()
+
+    private val dirs = listOf(
+        Position(0, 1),
+        Position(0, -1),
+        Position(1, 0),
+        Position(-1, 0),
+    )
+
+    fun solution() {
+
+        val (n, m) = readln().split(" ").map { it.toInt() }
+
+        repeat(n) {
+            val row = readln().split(" ").map {
+                if (it == "1") 3 else 0
+            } as MutableList
+            board.add(row)
+        }
+
+        var cnt = 0
+
+        while (board.flatten().any { it != 0 }) {
+
+            val queue: Queue<Position> = LinkedList()
+            val outsideAirStack = Stack<Position>()
+            val visited = Array(n) {
+                BooleanArray(m)
+            }
+
+            queue.add(Position(0, 0))
+            visited[0][0] = true
+
+            while (queue.isNotEmpty()) {
+
+                val cur = queue.poll()
+
+                dirs.forEach {
+                    val nx = it.x + cur.x
+                    val ny = it.y + cur.y
+
+                    if (nx !in 0 until n ||
+                        ny !in 0 until m ||
+                        visited[nx][ny]
+                    ) return@forEach
+
+                    if (board[nx][ny] == 0) {
+                        val next = Position(nx, ny)
+                        outsideAirStack.add(next)
+                        queue.add(next)
+                        visited[nx][ny] = true
+                    }
+                }
+            }
+
+            check(outsideAirStack)
+            board.melt()
+
+            cnt++
+
+        }
+
+        println(cnt)
+    }
+
+    private fun check(stack: Stack<Position>) {
+        while (stack.isNotEmpty()) {
+            val (i, j) = stack.pop()
+            val cur = board[i][j]
+            if (cur == 0) {
+
+                dirs.forEach {
+                    val nx = i + it.x
+                    val ny = j + it.y
+
+                    if (nx !in board.indices ||
+                        ny !in board.first().indices
+                    ) return@forEach
+
+                    if (0 < board[nx][ny]) board[nx][ny]--
+                }
+            }
+        }
+    }
+
+    private fun MutableList<MutableList<Int>>.melt() {
+        for (i in this.indices) {
+            for (j in this.first().indices) {
+                val cur = this[i][j]
+                if (cur == 1) this[i][j] = 0
+                else if (cur == 2) this[i][j] = 3
+            }
+        }
+    }
+}
+
+fun main() {
+    전현수_치즈().solution()
+}