Backspace String Compare

Author: P-ppc

README.md

@@ -120,6 +120,7 @@ All solutions will be accepted!
 |237|[Delete Node In A Linked List](https://leetcode-cn.com/problems/delete-node-in-a-linked-list/description/)|[java/py/js](./algorithms/DeleteNodeInALinkedList)|Easy|
 |405|[Convert A Number To Hexadecimal](https://leetcode-cn.com/problems/convert-a-number-to-hexadecimal/description/)|[java/py/js](./algorithms/ConvertANumberToHexadecimal)|Easy|
 |796|[Rotate String](https://leetcode-cn.com/problems/rotate-string/description/)|[java/py/js](./algorithms/RotateString)|Easy|
+|844|[Backspace String Compare](https://leetcode-cn.com/problems/backspace-string-compare/description/)|[java/py/js](./algorithms/BackspaceStringCompare)|Easy|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/BackspaceStringCompare/README.md

@@ -0,0 +1,2 @@
+# Backspace String Compare
+This problem is easy to solve by stack

algorithms/BackspaceStringCompare/Solution.java

@@ -0,0 +1,30 @@
+class Solution {
+    public boolean backspaceCompare(String S, String T) {
+        List<Character> sStack = new ArrayList<Character>();
+        List<Character> tStack = new ArrayList<Character>();
+        
+        for (char c : S.toCharArray()) {
+            if (c != '#') {
+                sStack.add(c);
+            } else if (sStack.size() > 0) {
+                sStack.remove(sStack.size() - 1);
+            }
+        }
+        
+        for (char c : T.toCharArray()) {
+            if (c != '#') {
+                tStack.add(c);
+            } else if (tStack.size() > 0) {
+                tStack.remove(tStack.size() - 1);
+            }
+        }
+        
+        char[] sArray = new char[sStack.size()];
+        for (int i = 0; i < sStack.size(); i++) sArray[i] = sStack.get(i);
+        
+        char[] tArray = new char[tStack.size()];
+        for (int i = 0; i < tStack.size(); i++) tArray[i] = tStack.get(i);
+        
+        return new String(sArray).equals(new String(tArray));
+    }
+}

algorithms/BackspaceStringCompare/solution.js

@@ -0,0 +1,27 @@
+/**
+ * @param {string} S
+ * @param {string} T
+ * @return {boolean}
+ */
+var backspaceCompare = function(S, T) {
+    let sStack = [],
+        tStack = []
+    
+    S.split('').forEach(c => {
+        if (c !== '#') {
+            sStack.push(c)
+        } else if (sStack.length > 0) {
+            sStack.pop()
+        }
+    })
+    
+    T.split('').forEach(c => {
+        if (c !== '#') {
+            tStack.push(c)
+        } else if (tStack.length > 0) {
+            tStack.pop()
+        }
+    })
+    
+    return sStack.join('') === tStack.join('')
+};

algorithms/BackspaceStringCompare/solution.py

@@ -0,0 +1,22 @@
+class Solution(object):
+    def backspaceCompare(self, S, T):
+        """
+        :type S: str
+        :type T: str
+        :rtype: bool
+        """
+        s_stack = []
+        t_stack = []
+        
+        for c in S:
+            if c != '#':
+                s_stack.append(c)
+            elif len(s_stack) > 0:
+                s_stack.pop()
+                
+        for c in T:
+            if c != '#':
+                t_stack.append(c)
+            elif len(t_stack) > 0:
+                t_stack.pop()
+        return ''.join(s_stack) == ''.join(t_stack)