Merge pull request #2542 from xqsrpanz/master

Update 0347.前K个高频元素.md

Author: youngyangyang04

problems/0347.前K个高频元素.md

@@ -405,6 +405,11 @@ class Heap {
 
     // 获取堆顶元素并移除
     pop() {
+        // 边界情况，只有一个元素或没有元素应直接弹出
+        if (this.size() <= 1) {
+            return this.queue.pop()
+        }
+
         // 堆顶元素
         const out = this.queue[0];
 
@@ -416,7 +421,7 @@ class Heap {
         let left = 1; // left 是左子节点下标 left + 1 则是右子节点下标
         let searchChild = this.compare(left, left + 1) > 0 ? left + 1 : left;
 
-        while (searchChild !== undefined && this.compare(index, searchChild) > 0) { // 注意compare参数顺序
+        while (this.compare(index, searchChild) > 0) { // 注意compare参数顺序
             [this.queue[index], this.queue[searchChild]] = [this.queue[searchChild], this.queue[index]];
 
             // 更新下标
@@ -608,3 +613,4 @@ impl Solution {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
+