饿了么笔试，算法红包题重构字符串题

第一题红包A 100%

function leastCost(nums, arr) {
  let dp = new Array(nums).fill(0);
  dp[0] = arr[0] / 2;
  dp[1] = Math.min(dp[0] + arr[1] - 5, arr[0] - 5 + arr[1] / 2);
  for (let i = 2; i < nums; i++) {
    dp[i] = Math.min(
      dp[i - 2] + arr[i - 1] - 5 + arr[i] / 2,
      dp[i - 1] + arr[i] - 5
    );
  }
  console.log(dp[nums - 1]);
}
// leastCost(4, [178, 15, 25, 178]);
// 208

直接dp，递推式：当天的最小代价取决于 前两天/2+前天-5+今天/2 和 前天/2+今天-5 的 最小值

第二题 字符串重构 A 90%

function restructString(str) {
  let newStr = str.split("");
  let mySet = new Set(newStr);
  let letter = [...mySet];
  let t = "";
  newStr.forEach((el) => {
    t += letter[(letter.indexOf(el) + 1) % letter.length];
  });
  console.log(t);
}
 // restructString("aabbc");
// bbcca