leetcode-algorithms/src/PathSum.java at master · anishLearnsToCode/leetcode-algorithms · GitHub

25 lines (19 loc) · 785 Bytes

public class PathSum {

public static boolean hasPathSum(TreeNode root, int sum) {

return root != null && hasPathSum(root, sum, root.val);

}

private static boolean hasPathSum(TreeNode root, int sum, int current) {

if (root == null) {

return false;

}

if (isLeafNode(root)) {

return sum == current;

}

boolean leftPathSumExists = root.left != null && hasPathSum(root.left, sum, current + root.left.val);

boolean rightPathSumExists = root.right != null && hasPathSum(root.right, sum, current + root.right.val);

return leftPathSumExists || rightPathSumExists;

}

private static boolean isLeafNode(TreeNode root) {

return root.left == null && root.right == null;

}

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