lintcode: Permutations II

Given a list of numbers with duplicate number in it. Find all unique permutations.

可以见我的博文全排列实现

class Solution {public:    /**     * @param nums: A list of integers.     * @return: A list of unique permutations.     */    vector<vector<int> >res;    void dfs(vector<int> &nums,vector<int> &sub,int cur){        if(cur==nums.size()){            res.push_back(sub);            return;        }        for(int i=0;i<nums.size();i++){            if(i==0||nums[i]!=nums[i-1]){                int c1=0,c2=0;                for(int j=0;j<nums.size();j++){                    if(nums[j]==nums[i]){                        c1++;                    }                }                for(int j=0;j<cur;j++){                    if(sub[j]==nums[i]){                        c2++;                    }                }                if(c2<c1){                    sub[cur]=nums[i];                    dfs(nums,sub,cur+1);                }            }        }    }    vector<vector<int> > permuteUnique(vector<int> &nums) {        // write your code here        int len=nums.size();        if(len==0){            return res;        }        sort(nums.begin(),nums.end());        vector<int> sub(len);        dfs(nums,sub,0);        return res;    }};