leetcode 46. Permutations

全排列，使用回溯法

 var permute = function (nums) {
      if (!Object(nums).length) {
        return [];
      }
      var result = [], condidate = [], n = nums.length, hash = {}
      function backtrack(start) {
        if (start === n) {//移动到最右边
          result.push(condidate.concat());
        } else {
          for (var i = 0; i < n; i++) {//注意从0开始，不断尝试
            if (hash[i]) {
              continue;
            }
            var el = nums[i]
            hash[i] = 1 //防止一个 condidate 数组添加了多个mums[i]
            condidate.push(el) //试探
            backtrack(start + 1); //递归自身
            hash[i] = 0
            condidate.pop(); //不管成功与否，退回上一步
          }
        }
      }
      backtrack(0); //此参数是用来决定索引是否移动到最右边
      return result;
    };

leetcode 46. Permutations

原文：https://www.cnblogs.com/rubylouvre/p/12045510.html