说起来这也算简单题, 第 1024 题纪念下.

const videoStitching = function (clips, T) {
  let clipsArr = new Array(T + 1).fill(-1), lastCur = 0, cur = 0, res = 0;
  for (let i = 0, clipsLen = clips.length; i < clipsLen; ++i) {
    if (clips[i][1] > clipsArr[clips[i][0]]) {
      clipsArr[clips[i][0]] = clips[i][1];
    }
  }
  if (clipsArr[0] >= T) {
    return 1;
  }
  if (clipsArr[0] === -1) {
    return -1;
  }
  for (let i = 0, clipsArrLen = clipsArr.length; i < clipsArrLen; ++i) {
    cur = Math.max(...clipsArr.slice(0, cur + 1));
    ++res;
    if (cur >= T) {
      return res;
    }
  }
  return -1;
};