Merge branch 'master' into master

problems/1047.删除字符串中的所有相邻重复项.md

@@ -11,7 +11,7 @@
 
 # 1047. 删除字符串中的所有相邻重复项
 
-[力扣题目链接](https://leetcode-cn.com/problems/remove-all-adjacent-duplicates-in-string/)
+[力扣题目链接](https://leetcode.cn/problems/remove-all-adjacent-duplicates-in-string/)
 
 给出由小写字母组成的字符串 S，重复项删除操作会选择两个相邻且相同的字母，并删除它们。
 
@@ -375,6 +375,7 @@ func removeDuplicates(_ s: String) -> String {
 }
 ```
 
+
 C#:
 ```csharp
 public string RemoveDuplicates(string s) {
@@ -392,5 +393,56 @@ public string RemoveDuplicates(string s) {
         return res.ToString();
     }
 ```
+
+
+PHP:
+```php
+class Solution {
+    function removeDuplicates($s) {
+        $stack = new SplStack();
+        for($i=0;$i<strlen($s);$i++){
+            if($stack->isEmpty() || $s[$i] != $stack->top()){
+                $stack->push($s[$i]);
+            }else{
+               $stack->pop(); 
+            }
+        }
+
+        $result = "";
+        while(!$stack->isEmpty()){
+            $result.= $stack->top();
+            $stack->pop();
+        }
+        
+        // 此时字符串需要反转一下
+        return strrev($result);
+    }
+}
+```
+
+
+Scala:
+```scala
+object Solution {
+  import scala.collection.mutable
+  def removeDuplicates(s: String): String = {
+    var stack = mutable.Stack[Int]()
+    var str = "" // 保存最终结果
+    for (i <- s.indices) {
+      var tmp = s(i)
+      // 如果栈非空并且栈顶元素等于当前字符，那么删掉栈顶和字符串最后一个元素
+      if (!stack.isEmpty && tmp == stack.head) {
+        str = str.take(str.length - 1)
+        stack.pop()
+      } else {
+        stack.push(tmp)
+        str += tmp
+      }
+    }
+    str
+  }
+}
+```
+
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