src/bin/kth-smallest-element-in-a-sorted-matrix.rs

Author: bestgopher

src/bin/kth-smallest-element-in-a-sorted-matrix.rs

@@ -0,0 +1,38 @@
+fn main() {}
+
+struct Solution;
+
+impl Solution {
+    /// 二分查找法？
+    pub fn kth_smallest(matrix: Vec<Vec<i32>>, k: i32) -> i32 {
+        let (mut left, mut right) = (matrix[0][0], matrix[matrix.len() - 1][matrix.len() - 1]);
+
+        while left < right {
+            let mid = left + (right - left) / 2;
+            let num = Self::get_number(&matrix[..], mid);
+            if num >= k {
+                right = mid;
+            } else {
+                left = mid + 1;
+            }
+        }
+        left
+    }
+
+    /// 求个数
+    fn get_number(matrix: &[Vec<i32>], mid: i32) -> i32 {
+        let (mut i, mut j) = (matrix.len() as i32 - 1, 0i32);
+        let mut num = 0;
+
+        while i >= 0 && j < matrix.len() as i32 {
+            if matrix[i as usize][j as usize] <= mid {
+                num += i as i32 + 1;
+                j += 1;
+            } else {
+                i -= 1;
+            }
+        }
+
+        num
+    }
+}