参考文字：C++ STL 全排列函数详解(排列组合与匹配算法)
#include <iostream> #include <algorithm> #include <vector> using namespace std; void printVec(vector<int> vec) { for (const int &k : vec) cout << k << " "; cout << endl; } /** * 测试全排列 * 输出： * 1 2 3 * 1 3 2 * 2 1 3 * 2 3 1 * 3 1 2 * 3 2 1 * 6 * */ void testFullPermutation(vector<int> vec) { //调用next_permutation前需排序才能获取全排列 sort(vec.begin(), vec.end()); int i = 0; do { printVec(vec); i++; } while (next_permutation(vec.begin(), vec.end())); cout << i << endl; } /** * 测试组合，n个数中取k个数 * 输出： * 1 2 * 1 3 * 2 3 * 3 **/ void testCombination(vector<int> set, int n, int k) { vector<int> p; p.insert(p.end(), k, 1); p.insert(p.end(), n - k, 0); size_t cnt = 0; do { vector<int> vec; for (int i = 0; i != p.size(); ++i) if (p[i]) vec.push_back(set[i]); printVec(vec); cnt++; } while (prev_permutation(p.begin(), p.end())); cout << cnt << endl; } int main(int argc, char *args[]) { vector<int> vec{1, 2, 3}; testFullPermutation(vec); testCombination(vec, 3, 2); getchar(); return 0; }