标签：uniq int ssi collect range bool possible example follow
Given a collection of numbers that might contain duplicates, return all possible unique permutations.
For example,[1,1,2] have the following unique permutations:
[ [1,1,2], [1,2,1], [2,1,1] ]
分析： 全组合的思想，保证start和end之间交换的时候中间没有与end相同的数字
class Solution {
public:
void swap(int i, int j, vector<int>& nums){
int temp =nums[i];
nums[i] = nums[j];
nums[j]= temp;
}
bool isSwap(int start, int end, vector<int>& nums){
for(; start<end; start++)
if(nums[start] == nums[end])
return false;
return true;
}
void allRange(int start, vector<int>& nums, vector<vector<int>>& res)
{
if(start==nums.size()-1)
return;
for(int i =start; i<nums.size(); i++){
if(isSwap(start,i,nums))
{
swap(start, i, nums);
if(start!=i)
res.push_back(nums);
allRange(start+1, nums, res);
swap(i, start, nums);
}
}
}
vector<vector<int>> permuteUnique(vector<int>& nums) {
vector<vector<int>> res;
if(nums.size()==0)
return res;
res.push_back(nums);
allRange(0, nums, res);
return res;
}
};
标签：uniq int ssi collect range bool possible example follow
原文地址：http://www.cnblogs.com/willwu/p/6227658.html
