Add kotlin code for dynamic programming (#1099)

* feat(kotlin): add kotlin code for dynamic programming. * Update knapsack.kt
2026-09-02 21:27:14 +00:00 · 2024-03-03 15:14:26 +08:00
parent 1db04577b5
commit 5c1f43fefd
12 changed files with 877 additions and 0 deletions
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+/**
+ * File: climbing_stairs_backtrack.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_dynamic_programming
+
+/* 回溯 */
+fun backtrack(
+    choices: List<Int>,
+    state: Int,
+    n: Int,
+    res: MutableList<Int>
+) {
+    // 当爬到第 n 阶时，方案数量加 1
+    if (state == n) res[0] = res[0] + 1
+    // 遍历所有选择
+    for (choice in choices) {
+        // 剪枝：不允许越过第 n 阶
+        if (state + choice > n) continue
+        // 尝试：做出选择，更新状态
+        backtrack(choices, state + choice, n, res)
+        // 回退
+    }
+}
+
+/* 爬楼梯：回溯 */
+fun climbingStairsBacktrack(n: Int): Int {
+    val choices = mutableListOf(1, 2) // 可选择向上爬 1 阶或 2 阶
+    val state = 0 // 从第 0 阶开始爬
+    val res = ArrayList<Int>()
+    res.add(0) // 使用 res[0] 记录方案数量
+    backtrack(choices, state, n, res)
+    return res[0]
+}
+
+/* Driver Code */
+fun main() {
+    val n = 9
+
+    val res = climbingStairsBacktrack(n)
+    println("爬 $n 阶楼梯共有 $res 种方案")
+}