Leetcode : Path Sum III

Author: spring0913

week10/Leetcode_(Path Sum III).java

@@ -0,0 +1,28 @@
+class Solution {
+    private int count;
+    private int targetSum;
+    private long[] sum;
+
+    public int pathSum(TreeNode root, int _targetSum) {
+        targetSum = _targetSum;
+        sum = new long[1001];
+        dfs(root, 1);
+        return count;
+    }
+
+    public void dfs(TreeNode node, int depth) {
+        if(node == null) {
+            return;
+        }
+
+        sum[depth] = sum[depth-1] + node.val;
+        for(int i=depth-1; i>=0; i--) {
+            if(sum[depth] - sum[i] == targetSum) {
+                count++;
+            }
+        }
+
+        dfs(node.left, depth+1);
+        dfs(node.right, depth+1);
+    }
+}