build

chapter_divide_and_conquer/binary_search_recur.md

@@ -247,3 +247,31 @@ status: new
 
     [class]{}-[func]{binarySearch}
     ```
+
+=== "Rust"
+
+    ```rust title="binary_search_recur.rs"
+    /* 二分查找：问题 f(i, j) */
+    fn dfs(nums: &[i32], target: i32, i: i32, j: i32) -> i32 {
+        // 若区间为空，代表无目标元素，则返回 -1
+        if i > j { return -1; }
+        let m: i32 = (i + j) / 2;
+        if nums[m as usize] < target {
+            // 递归子问题 f(m+1, j)
+            return dfs(nums, target, m + 1, j);
+        } else if nums[m as usize] > 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 */
+    fn binary_search(nums: &[i32], target: i32) -> i32 {
+        let n = nums.len() as i32;
+        // 求解问题 f(0, n-1)
+        dfs(nums, target, 0, n - 1)
+    }
+    ```