谜题
穷举一个数组中各个元素的排列
策略
减而治之、递归
javascript解
复制代码 代码如下:
/**
 * created by cshao on 12/23/14.
 */function getpermutation(arr) {
  if (arr.length == 1) {
    return [arr];
  }
  var permutation = [];
  for (var i=0; i    var firstele = arr[i];
    var arrclone = arr.slice(0);
    arrclone.splice(i, 1);
    var childpermutation = getpermutation(arrclone);
    for (var j=0; j      childpermutation[j].unshift(firstele);
    }
    permutation = permutation.concat(childpermutation);
  }
  return permutation;
}
var permutation = getpermutation(['a','b','c']);
console.dir(permutation);
结果
复制代码 代码如下:
[ [ 'a', 'b', 'c' ],
  [ 'a', 'c', 'b' ],
  [ 'b', 'a', 'c' ],
  [ 'b', 'c', 'a' ],
  [ 'c', 'a', 'b' ],
  [ 'c', 'b', 'a' ] ]