feat(kotlin): Add kotlin code for backtracking chapter (#1088)

* feat(kotlin):new kotlin support files * fix(kotlin): reviewed the formatting, comments and so on. * fix(kotlin): fix the indentation and format * feat(kotlin): Add kotlin code for the backtraking chapter. * fix(kotlin): fix incorrect output of preorder_traversal_iii_template.kt file * fix(kotlin): simplify kotlin codes * fix(kotlin): modify n_queens.kt for consistency.
2026-08-15 13:10:59 +00:00 · 2024-02-21 01:57:41 +08:00
parent e9341c51b5
commit 507357ace1
10 changed files with 603 additions and 0 deletions
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+/**
+ * File: preorder_traversal_iii_compact.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_backtracking.preorder_traversal_iii_compact
+
+import utils.TreeNode
+import utils.printTree
+
+var path: MutableList<TreeNode>? = null
+var res: MutableList<List<TreeNode>>? = null
+
+/* 前序遍历：例题三 */
+fun preOrder(root: TreeNode?) {
+    // 剪枝
+    if (root == null || root.value == 3) {
+        return
+    }
+    // 尝试
+    path!!.add(root)
+    if (root.value == 7) {
+        // 记录解
+        res!!.add(ArrayList(path!!))
+    }
+    preOrder(root.left)
+    preOrder(root.right)
+    // 回退
+    path!!.removeAt(path!!.size - 1)
+}
+
+/* Driver Code */
+fun main() {
+    val root = TreeNode.listToTree(mutableListOf(1, 7, 3, 4, 5, 6, 7))
+    println("\n初始化二叉树")
+    printTree(root)
+
+    // 前序遍历
+    path = ArrayList()
+    res = ArrayList()
+    preOrder(root)
+
+    println("\n输出所有根节点到节点 7 的路径，路径中不包含值为 3 的节点")
+    for (path in res as ArrayList<List<TreeNode>>) {
+        val values: MutableList<Int> = ArrayList()
+        for (node in path) {
+            values.add(node.value)
+        }
+        println(values)
+    }
+}