Javascript中的Itertools.combinations

function* combinations(arr, n) {
  if (n === 0) {
    yield [];
  } else {
    for (let i = 0; i <= arr.length - n; i++) {
      const head = arr.slice(i, i + 1);
      for (const tail of combinations(arr.slice(i + 1), n - 1)) {
        yield head.concat(tail);
      }
    }
  }
}

// 使用示例
const arr = [1, 2, 3, 4];
const n = 2;
for (const combo of combinations(arr, n)) {
  console.log(combo);
}

function* combinations(arr, n) {
  if (n === 0) {
    yield [];
  } else {
    for (let i = 0; i <= arr.length - n; i++) {
      const head = arr.slice(i, i + 1);
      for (const tail of combinations(arr.slice(i + 1), n - 1)) {
        yield head.concat(tail);
      }
    }
  }
}

// 使用示例并排序
const arr = [1, 2, 3, 4];
const n = 2;
const sortedCombos = [];
for (const combo of combinations(arr, n)) {
  sortedCombos.push(combo);
}
sortedCombos.sort((a, b) => {
  for (let i = 0; i < a.length; i++) {
    if (a[i] !== b[i]) return a[i] - b[i];
  }
  return 0;
});

console.log(sortedCombos);