https://leetcode.com/problems/path-sum/description/

RootToLeafPathSum.java

class RootToLeafPathSum {

    boolean result = false;
    int currentPathSum = 0;
    public static void main(String[] args) {
        TreeNode E1node7 = new TreeNode(7);
        TreeNode E1node2 = new TreeNode(2);
        TreeNode E1node1 = new TreeNode(1);
        TreeNode E1node11 = new TreeNode(11,E1node7, E1node2);
        TreeNode E1node13 = new TreeNode(13);
        TreeNode E1node4_R = new TreeNode(4, null, E1node1);
        TreeNode E1node8 = new TreeNode(8, E1node13, E1node4_R);
        TreeNode E1node4_L = new TreeNode(4, E1node11, null);
        TreeNode E1node5 = new TreeNode(5,E1node4_L,E1node8);
        System.out.println(new RootToLeafPathSum().hasPathSum(E1node5, 22));

        TreeNode E2nodeN1 = new TreeNode(-1);
        TreeNode E2node3 = new TreeNode(3);
        TreeNode E2nodeN2 = new TreeNode(-2);
        TreeNode E2nodeN3 = new TreeNode(-3, E2nodeN2, null);
        TreeNode E2node1_L = new TreeNode(1,E2nodeN1, null);
        TreeNode E2nodeN2_L = new TreeNode(-2, E2node1_L, E2node3);
        TreeNode E2node1 = new TreeNode(1, E2nodeN2_L, E2nodeN3);
        System.out.println(new RootToLeafPathSum().hasPathSum(E2node1, 2));
    }

    public boolean hasPathSum(TreeNode root, int targetSum) {
        if(root!=null){
            currentPathSum = currentPathSum + root.val;
            if(root.left==null && root.right==null){
                if(targetSum == currentPathSum){
                    result = true;
                    return result;
                }else
                    currentPathSum = currentPathSum - root.val;
            }else{
                if(root.left!=null)
                    hasPathSum(root.left, targetSum);
                if(root.right!=null)
                    hasPathSum(root.right, targetSum);
                currentPathSum = currentPathSum - root.val;
            }
            return result;
        }
        return result;
    }
}

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode() {}
    TreeNode(int val) { this.val = val; }
    TreeNode(int val, TreeNode left, TreeNode right) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}