function minAvgTwoSlice(a: number[]): number {
  let idx = 0;
  let min = (a[0] + a[1]) / 2;

  for (let i = 0; i < a.length - 1; i++) {
    let cur = (a[i] + a[i + 1]) / 2;
    if (a[i + 2] !== undefined) {
      const three = (a[i] + a[i + 1] + a[i + 2]) / 3;
      cur = cur < three ? cur : three;
    }
    if (cur < min) {
      min = cur;
      idx = i;
    }
  }

  return idx;
}