feat: Add Dart codes for chapter_backtracking and chapter_divide_and_conquer (#680)

* feat: Add Dart codes for chapter_backtracking * feat: Add Dart codes for chapter_divide_and_conquer * Format Dart Code
2026-08-21 15:57:14 +00:00 · 2023-08-10 23:48:56 +08:00
parent e97eee0e18
commit 4325974af1
19 changed files with 731 additions and 18 deletions
@@ -0,0 +1,42 @@
+/**
+ * File: binary_search_recur.dart
+ * Created Time: 2023-08-10
+ * Author: liuyuxin (gvenusleo@gmail.com)
+ */
+
+/* 二分查找：问题 f(i, j) */
+int dfs(List<int> nums, int target, int i, int j) {
+  // 若区间为空，代表无目标元素，则返回 -1
+  if (i > j) {
+    return -1;
+  }
+  // 计算中点索引 m
+  int m = (i + j) ~/ 2;
+  if (nums[m] < target) {
+    // 递归子问题 f(m+1, j)
+    return dfs(nums, target, m + 1, j);
+  } else if (nums[m] > target) {
+    // 递归子问题 f(i, m-1)
+    return dfs(nums, target, i, m - 1);
+  } else {
+    // 找到目标元素，返回其索引
+    return m;
+  }
+}
+
+/* 二分查找 */
+int binarySearch(List<int> nums, int target) {
+  int n = nums.length;
+  // 求解问题 f(0, n-1)
+  return dfs(nums, target, 0, n - 1);
+}
+
+/* Driver Code */
+void main() {
+  int target = 6;
+  List<int> nums = [1, 3, 6, 8, 12, 15, 23, 26, 31, 35];
+
+  // 二分查找（双闭区间）
+  int index = binarySearch(nums, target);
+  print("目标元素 6 的索引 = $index");
+}