#include <iostream> #include <algorithm> #include <string> #include <queue> #include <map> using namespace std; int n, k; int BFS(string s, string ans) { queue< pair<string, pair<int, int> > > q; q.push({ s, {0, -1} }); map<string, bool> mp; while(!q.empty()){ string x=q.front().first; int cnt=q.front().second.first, prv=q.front().second.second; q.pop(); if(x==ans){ return cnt; } if(mp.count(x)){ continue; } mp[x]=1; for(int i=0; i<n-1; i++){ if(i==prv){ continue; } string sub=x.substr(i, x.size()); reverse(sub.begin(), sub.end()); string nxt=x.substr(0, i)+sub; if(mp.count(nxt)==0){ q.push({nxt, {cnt+1, i}}); } } } } void solve() { cin >> n; string s; vector< pair<int, int> > v; for(int i=0; i<n; i++){ int a; cin >> a; v.push_back({a, i}); s+=(i+'1'); } sort(v.begin(), v.end()); string ans; for(int i=n-1; i>=0; i--){ ans+=v[i].second+'1'; } cout << BFS(s, ans) << "\n"; } int main() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); int t; cin >> t; while(t--){ solve(); } return 0; }

pancake.cpp: In function 'int BFS(std::string, std::string)':
pancake.cpp:13:44: warning: control reaches end of non-void function [-Wreturn-type]
   13 |     queue< pair<string, pair<int, int> > > q;
      |                                            ^