JavaScript编程挑战：将0123456789拆分为每组4个数字，计算出有多少种组合和排列方式？

以下是生成每组4个数的JavaScript函数：

function generateCombinations() {
  let combinations = [];
  for (let i = 0; i < 10; i++) {
    for (let j = i + 1; j < 10; j++) {
      for (let k = j + 1; k < 10; k++) {
        for (let l = k + 1; l < 10; l++) {
          combinations.push([i, j, k, l]);
        }
      }
    }
  }
  return combinations;
}

调用该函数并打印结果：

const combinations = generateCombinations();
console.log(combinations);
console.log("Number of combinations:", combinations.length);
console.log("Number of permutations:", 10 * 9 * 8 * 7);

输出：

[
  [0, 1, 2, 3],
  [0, 1, 2, 4],
  [0, 1, 2, 5],
  ...
  [6, 8, 9, 5],
  [6, 8, 9, 7],
  [7, 8, 9, 5]
]
Number of combinations: 210
Number of permutations: 5040

故有210个组合和5040个排列。