请实现下面的 treePath 方法

/**
 * @file 二叉树所有路径
 */

type Tree = {
    value: number;
    left?: Tree;
    right?: Tree;
}
const tree: Tree = {
    value: 1,
    left: {
        value: 2,
        right: { value: 5 }
    },
    right: { value: 3 }
};
function treePath(root: Tree): string[] {
    // 补全此处代码
    throw new Error('功能待实现');
}
console.log(treePath(tree)) // [ '1->2->5', '1->3' ]

export default {}

参考答案

/**
 * @file 二叉树所有路径
 */

type Tree = {
  value: number;
  left?: Tree;
  right?: Tree;
};

const tree: Tree = {
  value: 1,
  left: {
    value: 2,
    right: { value: 5 },
  },
  right: { value: 3 },
};

function treePath(root: Tree): string[] {
  const answer: [] = [];
  let tmp: [][] = [];
  const travel = (r: Tree) => {
    if (r == null) {
      return;
    }
    //@ts-ignore
    tmp.push(r.value);
    if (r.left == null && r.right == null) {
      //@ts-ignore
      answer.push(tmp);
      tmp = [tmp[0]];
      return;
    }
    if (r.left) travel(r.left);
    if (r.right) travel(r.right);
  };
  travel(root);
  //@ts-ignore
  return answer.map((t) => t.join("->"));
}
console.log(treePath(tree)); // [ '1->2->5', '1->3' ]

export default {};