Contest/src/_20160924_6th_contest/SumofLeftLeaves.java

fishercoder1534 · fishercoder1534 · commit e568808e836f · 2016-09-24T23:52:55.000-07:00
diff --git a/Contest/src/_20160924_6th_contest/SumofLeftLeaves.java b/Contest/src/_20160924_6th_contest/SumofLeftLeaves.java
@@ -0,0 +1,29 @@
+package _20160924_6th_contest;
+
+import classes.TreeNode;
+
+public class SumofLeftLeaves {
+    public int sumOfLeftLeaves(TreeNode root) {
+        int result = 0;
+        if(root == null) return result;
+        return dfs(root, result, false);
+    }
+    
+    private int dfs(TreeNode root, int result, boolean left) {
+        if(root.left == null && root.right == null && left) {
+            result += root.val;
+            return result;
+        }
+        int leftResult = 0;
+        if(root.left != null){
+            left = true;
+            leftResult = dfs(root.left, result, left);
+        }
+        int rightResult = 0;
+        if(root.right != null){
+            left = false;
+            rightResult = dfs(root.right, result, left);
+        }
+        return leftResult + rightResult;
+    }
+}
