Update 0112-path-sum.java

#2510

Author: Anukriti167

Diff for: java/0112-path-sum.java

@@ -14,20 +14,17 @@
  * }
  */
 class Solution {
-    private boolean isLeafNode(TreeNode node) {
-        return ((node.left == null) && (node.right == null));
-    }
-
-    public boolean hasPathSum(TreeNode root, int targetSum) {
-        // Edge case: No nodes
-        if(root == null) {
-            return false;
-        }
+    //This would be easily solved by DFS and then comparing the values
+    public boolean dfs(TreeNode root, int targetSum, int currSum){
+        if(root == null) return false;
 
-        targetSum -= root.val;
-        if(isLeafNode(root)) {
-            return (targetSum == 0);
+        currSum += root.val;
+        if(root.left == null && root.right == null){
+            return (currSum == targetSum);
         }
-        return hasPathSum(root.left, targetSum) || hasPathSum(root.right, targetSum);
+        return dfs(root.left, targetSum, currSum) || dfs(root.right, targetSum, currSum);
+    }
+    public boolean hasPathSum(TreeNode root, int targetSum) {
+        return dfs(root, targetSum, 0);
     }
-}
+}