回溯例子记录

// 回溯最主要还是那个index
const sku = () => {
  let iphone = ["11", "12"];
  let color = ["red", "blue"];
  let memory = ["64", "256"];

  const combine = (...chunks: string[][]) => {
    console.log(chunks);
    let res: string[][] = [];
    const helper = (chunkIndex: number, prev: string[]) => {
      let chunk = chunks[chunkIndex];
      let isLast = chunkIndex === chunks.length - 1;
      for (let val of chunk) {
        let cur = prev.concat(val);
        if (isLast) {
          res.push(cur);
        } else {
          console.log(cur);
          helper(chunkIndex + 1, cur);
        }
      }
    };
    helper(0, []);
    return res;
  };
  console.log(combine(iphone, color, memory));
};
//暴力回溯
const combine = (n: number, k: number): number[][] => {
  const ans: number[][] = [];
  let temp: number[] = [];
  const dfs = (n: number, k: number, cur: number) => {
    if (temp.length === k) {
      ans.push([...temp]);
    }
    for (let i = cur; i <= n; i++) {
      temp.push(i);
      dfs(n, k, i + 1);
      temp.pop();
    }
  };
  dfs(n, k, 1);
  console.log(ans);
  return ans;
};