Merge pull request #2140 from Lozakaka/patch-28

新增java：用最長公共子序列反推

problems/0583.两个字符串的删除操作.md

@@ -189,6 +189,31 @@ class Solution {
     }
 }
 ```
+```java
+//DP - longest common subsequence (用最長公共子序列反推)
+class Solution {
+    public int minDistance(String word1, String word2) {
+        char[] char1 = word1.toCharArray();
+        char[] char2 = word2.toCharArray();
+
+        int len1 = char1.length;
+        int len2 = char2.length;
+
+        int dp[][] = new int [len1 + 1][len2 + 1];
+
+        for(int i = 1; i <= len1; i++){
+            for(int j = 1; j <= len2; j++){
+                if(char1[i - 1] == char2[j - 1])
+                    dp[i][j] = dp[i - 1][j - 1] + 1;
+                else
+                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
+            }
+        }
+
+        return len1 + len2 - (2 * dp[len1][len2]);//和leetcode 1143只差在這一行。
+    }
+}
+```
 
 
 Python：