int maxwidth(struct TreeNode* root) {
    if (!root) {
        return 0;
    }
    int maxWidth = 0;
    struct TreeNode** queue = (struct TreeNode**) malloc(sizeof(struct TreeNode*) * 1000);
    int front = 0, rear = 0;
    queue[rear++] = root;
    while (front != rear) {
        int size = rear - front;
        int leftmost = 0, rightmost = 0;
        for (int i = 0; i < size; i++) {
            struct TreeNode* node = queue[front++];
            if (i == 0) {
                leftmost = node->val;
            }
            if (i == size - 1) {
                rightmost = node->val;
            }
            if (node->left) {
                node->left->val = node->val * 2;
                queue[rear++] = node->left;
            }
            if (node->right) {
                node->right->val = node->val * 2 + 1;
                queue[rear++] = node->right;
            }
        }
        int width = rightmost - leftmost + 1;
        maxWidth = maxWidth < width ? width : maxWidth;
    }
    free(queue);
    return maxWidth;
}