46、47-Permutations

题目描述

46-Permutations I:

47-Permutations II:

算法分析

代码实现

//  use function next_permutation
class Solution {
public:
vector<vector<int>> permute(vector<int>& nums) {
vector<vector<int>> result;
sort(nums.begin(), nums.begin()+nums.size());
do {
result.push_back(nums);
} while (next_permutation(nums.begin(), nums.begin() + nums.size()));
return result;
}
};

class Solution {
public:
vector<vector<int>> permuteUnique(vector<int>& nums) {
vector<vector<int>> result;
sort(nums.begin(), nums.begin()+nums.size());
do {
result.push_back(nums);
} while (next_permutation(nums.begin(), nums.begin() + nums.size()));
int n = result.size();
for (int i = 0; i < result.size(); ++i) {
for (int j = i + 1; j < result.size(); ++j) {
if (isSame(result[i], result[j]))
result.erase(result.begin() + j);
}
}
return result;
}
bool isSame(vector<int> a, vector<int> b) {
int n = a.size();
for (int i = 0; i < n; ++i) {
if (a[i] != b[i]) return false;
}
return true;
}
};