Merge pull request #555 from YellowPeaches/master

update 0100相同的树java版

problems/0100.相同的树.md

@@ -172,6 +172,22 @@ public:
 
 Java：
 
+```java
+class Solution {
+    public boolean isSameTree(TreeNode p, TreeNode q) {
+        if (p == null && q == null) {
+            return true;
+        } else if (q == null || p == null) {
+            return false;
+        } else if (q.val != p.val) {
+            return false;
+        } else {
+            return isSameTree(q.left, p.left) && isSameTree(q.right, p.right);
+        }
+    }
+}
+
+```
 Python：
 
 Go：