腾讯公众号&小程序团队前端实习生一面 #

/*
吃饼干
小华有m块饼干要吃n天，每天至少吃前一天的一半，求第一天最多吃多少块，如果为0输出-1
*/
function mostEaten(m: number, n: number) {
  function calc(num: number) {
    let sum = 0;
    for (let i = 0; i < n; i++) {
      sum += num < 1 ? 1 : num;
      num = Math.ceil(num / 2);
    }
    return sum;
  }
  let left = 0,
    right = m;
  while (left < right) {
    const mid = (left + right) >> 1;
    const temp = calc(mid);
    if (temp === m) {
      return mid;
    } else if (temp > m) {
      right = mid;
    } else {
      left = mid + 1;
    }
  }
  if (left === 0) {
    return -1;
  }
}

/*
最近公共父节点
*/
function lowestCommonAncestor(
  root: TreeNode | null,
  p: TreeNode | null,
  q: TreeNode | null
): TreeNode | null {
  if (!root || root === p || root === q) {
    return root;
  }
  const left = lowestCommonAncestor(root.left, p, q);
  const right = lowestCommonAncestor(root.right, p, q);
  if (left && right) {
    return root;
  }
  if (!left && right) {
    return right;
  }
  if (!right && left) {
    return left;
  }
  return null;
}

/*
经典HardMan
*/
function sleep(delay: number) {
  return () =>
    new Promise(resolve => {
      const time = +new Date();
      console.log("等待开始: 0s");
      setTimeout(() => {
        console.log(`等待结束: ${~~((+new Date() - time) / 1000)}s`);
        resolve(void 0);
      }, delay * 1000);
    });
}
function HardMan(name: string) {
  const taskQueues: Function[][] = [[() => console.log(`i am ${name}`)]];
  let index = 0;
  setTimeout(async () => {
    for (let taskQueue of taskQueues) {
      for (let task of taskQueue) {
        await task();
      }
    }
  });
  const value = {
    rest(delay: number) {
      taskQueues[index].push(sleep(delay));
      return this;
    },
    restFirst(delay: number) {
      taskQueues[index].unshift(sleep(delay));
      return this;
    },
    learn(subject: string) {
      taskQueues[index].push(() => {
        console.log(`learning ${subject}`);
      });
      taskQueues[++index] = [];
      return this;
    },
  };
  return value;
}

HardMan("jack");
// i am jack

HardMan("jack").rest(3).learn("computer");
// i am jack
// 等待开始: 0s
// 等待结束: 3s
// learning computer

HardMan("jack").restFirst(5).learn("chinese");
// 等待开始: 0s
// 等待结束: 5s
// i am jack
// learning chinese

HardMan("jack")
  .restFirst(3)
  .learn("Chinese")
  .learn("English")
  .rest(2)
  .learn("Japanese");
// 等待开始: 0s
// 等待结束: 3s
// i am jack
// learning Chinese
// learning English
// 等待开始: 0s
// 等待结束: 2s
// learning Japanese