Merge pull request #119 from Winniekun/master

添加0072.编辑距离 Java版本

problems/0072.编辑距离.md

@@ -198,7 +198,32 @@ public:
 
 
 Java：
-
+```java
+public int minDistance(String word1, String word2) {
+    int m = word1.length();
+    int n = word2.length();
+    int[][] dp = new int[m + 1][n + 1];
+    // 初始化
+    for (int i = 1; i <= m; i++) {
+        dp[i][0] =  i;
+    }
+    for (int j = 1; j <= n; j++) {
+        dp[0][j] = j;
+    }
+    for (int i = 1; i <= m; i++) {
+        for (int j = 1; j <= n; j++) {
+            // 因为dp数组有效位从1开始
+            // 所以当前遍历到的字符串的位置为i-1 | j-1
+            if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
+                dp[i][j] = dp[i - 1][j - 1];
+            } else {
+                dp[i][j] = Math.min(Math.min(dp[i - 1][j - 1], dp[i][j - 1]), dp[i - 1][j]) + 1;
+            }
+        }
+    }
+    return dp[m][n];
+}
+```
 
 Python：