[1022] 从根到叶的二进制数之和

details

var sumRootToLeaf = function (root) {
    const ans = [];
    dfs(root, []);
    function dfs(root, path) {
        if (root === null) {
            return;
        }

        // Include the current node's value in the path
        path = path.concat(root.val);

        // If it's a leaf node (no children), push the path into ans
        if (root.left === null && root.right === null) {
            ans.push(path);
            return;
        }

        // Recursively traverse the left and right children
        dfs(root.left, path);
        dfs(root.right, path);
    }
    return ans.reduce((acc, arr) => {
        const len = arr.length - 1;
        arr.forEach((val, i) => {
            acc += val * 2 ** (len - i);
        });
        return acc;
    }, 0);
};

var sumRootToLeaf = function (root) {
    // Helper function to perform DFS
    function dfs(node, currentSum) {
        if (node === null) return 0;

        // Update the current sum by shifting left and adding the node's value
        currentSum = (currentSum << 1) | node.val;

        // If it's a leaf node, return the current sum
        if (node.left === null && node.right === null) {
            return currentSum;
        }

        // Recurse on left and right children
        return dfs(node.left, currentSum) + dfs(node.right, currentSum);
    }

    // Start DFS from the root with an initial sum of 0
    return dfs(root, 0);
};