UVA_10570_Meeting with Aliens

#include<iostream>#include<sstream>#include<string>#include<vector>#include<list>#include<set>#include<map>#include<stack>#include<queue>#include<algorithm>#pragma warning(disable:4996)#include<cstdio>#include<cstdlib>using std::cin;using std::cout;using std::endl;using std::stringstream;using std::string;using std::vector;using std::list;using std::pair;using std::set;using std::multiset;using std::map;using std::multimap;using std::stack;using std::queue;using std::priority_queue;int exchange(vector<int>order){int n = 0;//升序for (size_t i = 0; i < order.size(); i++){while (order[i] != i){std::swap(order[i],order[order[i]]);n++;}}return n;}int main(){//freopen("input.txt", "r", stdin);  //freopen("output.txt", "w", stdout);  int n;while (cin >> n&&n){vector<int>order(n);for (int i = 0; i < n; i++){cin >> order[i];order[i]--;}for (int i = 0; i < n; i++){order.push_back(order[i]);}int count = 1000000000;for (int i = 0; i < n; i++){vector<int>tmp;tmp.assign(order.begin()+i,order.begin()+i+n);count = std::min(count, exchange(tmp));std::reverse(tmp.begin(), tmp.end());count = std::min(count, exchange(tmp));if (!count){break;}}cout << count << endl;}return 0;}