From 642734522dcb0aa693ab651a6591fd315a721db2 Mon Sep 17 00:00:00 2001
From: ekertree <ekertree@qq.com>
Date: Thu, 18 Aug 2022 20:07:34 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200844=E6=AF=94=E8=BE=83?=
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---
 problems/0844.比较含退格的字符串.md | 75 +++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/problems/0844.比较含退格的字符串.md b/problems/0844.比较含退格的字符串.md
index f7823e59..5d29ffb0 100644
--- a/problems/0844.比较含退格的字符串.md
+++ b/problems/0844.比较含退格的字符串.md
@@ -157,7 +157,7 @@ public:
 
 ## 其他语言版本
 
-### Java：
+### Java
 
 ```java
 // 普通方法（使用栈的思路）
@@ -214,7 +214,80 @@ public static boolean backspaceCompare(String s, String t) {
 }
 ```
 
+```java
+class Solution {
+    public static boolean backspaceCompare(String s, String t) {
+        return getStr(s).equals(getStr(t));
+    }
 
+    public static String getStr(String s) { //使用快慢双指针去除字符串中的#
+        int slowIndex;
+        int fastIndex = 0;
+        StringBuilder builder = new StringBuilder(s); //StringBuilder用于修改字符串
+        for(slowIndex = 0; fastIndex < s.length(); fastIndex++) {
+            if(builder.charAt(fastIndex) != '#') {
+                builder.setCharAt(slowIndex++,builder.charAt(fastIndex));
+            } else {
+                if(slowIndex > 0) {
+                    slowIndex--;
+                }
+            }
+        }
+        return builder.toString().substring(0,slowIndex); //截取有效字符串
+    }
+}
+```
+
+从后往前双指针：
+
+```java
+class Solution {
+    public static boolean backspaceCompare(String s, String t) {
+        int sSkipNum = 0; //记录s的#的个数
+        int tSkipNum = 0; //记录t的#的个数
+        int sIndex = s.length() - 1;
+        int tIndex = t.length() - 1;
+        while(true) {
+            while(sIndex >= 0) { //每次记录连续的#并跳过被删除的字符
+                if(s.charAt(sIndex) == '#') {
+                    sSkipNum++;
+                } else {
+                    if(sSkipNum > 0) {
+                        sSkipNum--;
+                    } else {
+                        break;
+                    }
+                }
+                sIndex--;
+            }
+            while(tIndex >= 0) { //每次记录连续的#并跳过被删除的字符
+                if(t.charAt(tIndex) == '#') {
+                    tSkipNum++;
+                } else {
+                    if(tSkipNum > 0) {
+                        tSkipNum--;
+                    } else {
+                        break;
+                    }
+                }
+                tIndex--;
+            }
+            if(sIndex < 0 || tIndex < 0) { //s 或者 t遍历完了
+                break;
+            }
+            if(s.charAt(sIndex) != t.charAt(tIndex)) { //当前下标的字符不相等
+                return false;
+            }
+            sIndex--;
+            tIndex--;
+        }
+        if(sIndex == -1 && tIndex == -1) { //同时遍历完 则相等
+            return true;
+        }
+        return false;
+    }
+}
+```
 
 ### python