feat(heap): add 1046_last_stone_weight.rs

Author: whisperpine

README.md

@@ -159,3 +159,4 @@ so that you can use `just tf TEST` command to test.
 | Problem | Difficulty | Solution |
 | - | - | - |
 | 703. Kth Largest Element in a Stream | Easy | [703_kth_largest_element_in_a_stream.rs](./tests/703_kth_largest_element_in_a_stream.rs) |
+| 1046. Last Stone Weight | Easy | [1046_last_stone_weight.rs](./tests/1046_last_stone_weight.rs) |

tests/1046_last_stone_weight.rs

@@ -0,0 +1,32 @@
+// 1046. Last Stone Weight
+// https://leetcode.com/problems/last-stone-weight/description/
+// Topics: Heap / Priority Queue.
+// Difficulty: Easy.
+
+#![allow(unused)]
+
+#[test]
+fn test_1046_last_stone_weight() {}
+
+#[derive(Debug)]
+pub struct Solution;
+
+// ---------------------------------
+// copy to leetcode starts from here
+// ---------------------------------
+
+impl Solution {
+    pub fn last_stone_weight(stones: Vec<i32>) -> i32 {
+        use std::collections::BinaryHeap;
+        let mut heap: BinaryHeap<i32> = BinaryHeap::from(stones);
+        while heap.len() >= 2 {
+            let x = heap.pop().unwrap();
+            let y = heap.pop().unwrap();
+            let diff = (x - y).abs();
+            if diff != 0 {
+                heap.push(diff);
+            }
+        }
+        *heap.peek().unwrap_or(&0)
+    }
+}