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Path Sum

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.

A leaf is a node with no children.

public boolean hasPathSum(TreeNode root, int sum) {
    // iteration method
    if (root == null) {return false;}
    Stack<TreeNode> path = new Stack<>();
    Stack<Integer> sub = new Stack<>();
    path.push(root);
    sub.push(root.val);
    while (!path.isEmpty()) {
        TreeNode temp = path.pop();
        int tempVal = sub.pop();
        if (temp.left == null && temp.right == null) {if (tempVal == sum) return true;}
        else {
            if (temp.left != null) {
                path.push(temp.left);
                sub.push(temp.left.val + tempVal);
            }
            if (temp.right != null) {
                path.push(temp.right);
                sub.push(temp.right.val + tempVal);
            }
        }
    }
    return false;
}

Posted by Jamie Meyer 4 months ago

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