Submission #1088650

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088650		vjudge1	Xor Sort (eJOI20_xorsort)	C++17	0 / 100	1103 ms	207412 KiB

xorsort

#include <bits/stdc++.h>
using namespace std;
#define fastinput cin.tie(nullptr)->sync_with_stdio(false);
#define endl '\n'
#define ll long long
const ll mOd=1e9+7;
const int mAx=INT_MAX;
const int nUm=1e3+3;
vector<int>a;
int n,s;
bool srtd(vector<int>b){
    for(int i=0 ; i<b.size()-1 ; i++){
        if((s==1 && b[i]>=b[i+1]) || (s==2 && b[i]>b[i+1]))
        return 0;
    }
    return 1;
}
vector<pair<int,int>>bfs(){
    queue<pair<vector<int>,vector<pair<int,int>>>>q;
    map<vector<int>,bool>vis;
    q.push({a,{}});
    vis[a]=1;
    while(!q.empty()){
        auto [x,y]=q.front(); q.pop();
        if(srtd(x)) return y;
        for(int i=0 ; i<x.size()-1 ; i++){
            vector<int>v=x;
            v[i]=x[i]^x[i+1];
            if(!vis[v])
            {
                vis[v]=1;
                auto z=y;
                z.push_back({i,i+1});
                q.push({v,z});
            }
            v=x;
            v[i+1]=x[i]^x[i+1];
            if(!vis[v])
            {
                vis[v]=1;
                auto z=y;
                z.push_back({i+1,i});
                q.push({v,z});
            }
        }
    }
    return {};
}
int main()
{
    fastinput;
    cin>>n>>s;
    for(int i=0 ; i<n ; i++){
        int x; cin>>x;
        a.push_back(x);
    }
    vector<pair<int,int>>v=bfs();
    cout<<v.size()<<endl;
    for(auto it:v)cout<<it.first+1<<" "<<it.second+1<<endl;
}

Compilation message (stderr)

xorsort.cpp: In function 'bool srtd(std::vector<int>)':
xorsort.cpp:12:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for(int i=0 ; i<b.size()-1 ; i++){
      |                   ~^~~~~~~~~~~
xorsort.cpp: In function 'std::vector<std::pair<int, int> > bfs()':
xorsort.cpp:26:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |         for(int i=0 ; i<x.size()-1 ; i++){
      |                       ~^~~~~~~~~~~

• Subtask 1: 0 / 25
• Subtask 2: 0 / 35
• Subtask 3: 0 / 40