257.二叉树的所有路径【简单题】

题目链接

// 升级一下initTree的代码
const initTree = (inputList) => {
    const total = inputList.length;
    if(!inputList[0])return null;
    inputList[0] = new TreeNode(inputList[0]);
    inputList.forEach((el,index) => {
        let leftP = null;
        let rightP = null;
        if (el === null) return;
        if (index*2+1 < total) {
            leftP = inputList[index*2+1] !== null ? new TreeNode(inputList[index*2+1]): null;
            inputList[index*2+1] = leftP;
        } 
        if (index*2+2 < total) {
            rightP = inputList[index*2+2] !== null ? new TreeNode(inputList[index*2+2]): null;
            inputList[index*2+2] = rightP;
        }
        inputList[index].left = leftP;
        inputList[index].right = rightP;
    });
    return inputList[0];
}

function TreeNode(val, left, right) {
    this.val = (val===undefined ? 0 : val)
    this.left = (left===undefined ? null : left)
    this.right = (right===undefined ? null : right)
}

const getAllPath = (curNode, curPath, paths) => {
    curPath.push(curNode.val)
    if (!curNode.left && !curNode.right) {
        paths.push(curPath);
        return 
    }
    if(curNode.left)getAllPath(curNode.left, [...curPath], paths);
    if(curNode.right)getAllPath(curNode.right, [...curPath], paths);
}

const formatted = (paths) => {
    const res = [];
    paths.forEach(list=>{
        res.push(list.join('->'));
    })
    return res;
}

/**
 * @param {TreeNode} root
 * @return {string[]}
 */
var binaryTreePaths = function(root) {
    if (!root) return [];
    const paths = [];
    getAllPath(root, [], paths);
    return formatted(paths);
};

// 验证代码
(()=>{
    // const input = [1,2,3,null,5];
    const input = [];
    const root = initTree(input);
    console.log('root', root);
    console.log('binaryTreePaths', binaryTreePaths(root));
})();