前端算法js：跳格子有多少种走法-斐波拉切数列

// 前端算法js：跳格子有多少种走法-斐波拉切数列
function totalNum(num) {
  if (num == 1) {
    return 1;
  }
  if (num == 2) {
    return 2;
  }
  if (num > 2) {
    return totalNum(num - 1) + totalNum(num - 2); // 递归
  }
}
console.log(totalNum(2));
console.log(totalNum(3));
console.log(totalNum(40));
function gh(num) {
  let arr = [0, 1, 2];
  for (let i = 3; i <= num; i++) {
    arr[i] = arr[i - 1] + arr[i - 2]; // 动态规划
  }
  return arr[num];
}
console.log(gh(2)); // 2
console.log(gh(3)); // 3
console.log(gh(40)); // 165580141