Create Solution.java

Jerring · web-flow · commit 5fa4ede466c4 · 2019-06-15T15:38:23.000+08:00
diff --git a/solution/0687.Longest Univalue Path/Solution.java b/solution/0687.Longest Univalue Path/Solution.java
@@ -0,0 +1,19 @@
+class Solution {
+    public int longestUnivaluePath(TreeNode root) {
+        int[] res = new int[1];
+        dfs(root, res);
+        return res[0];
+    }
+
+    private int dfs(TreeNode root, int[] res) {
+        if (root == null) {
+            return 0;
+        }
+        int left = dfs(root.left, res);
+        int right = dfs(root.right, res);
+        left = root.left != null && root.left.val == root.val ? left + 1 : 0;
+        right = root.right != null && root.right.val == root.val ? right + 1 : 0;
+        res[0] = Math.max(res[0], left + right);
+        return Math.max(left, right);
+    }
+}
