Submission #1309678

#	Time	Username	Problem	Language	Result	Execution time	Memory
1309678		coderg	Xor Sort (eJOI20_xorsort)	C++20	0 / 100	1 ms	336 KiB

xorsort

#include "bits/stdc++.h"
using namespace std;
#define mp make_pair
#define fi first
#define se second
#define pii pair<int,int>
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define pb push_back
void setIO(string name = ""){if(name.size()){ freopen((name + ".in").c_str(), "r", stdin);freopen((name + ".out").c_str(), "w", stdout);}}
#define F(i,l,r) for(int i=(l);i<(r);++i)
#define FR(i,l,r) for(int i=(l);i>=(r);--i)
typedef long long ll;

const int maxn=2005;
const int mod=1e9+7;
//const ll inf=1e20;

void solve(){
int n,s;
cin>>n>>s;
vector<int> a(n);
F(i,0,n)cin>>a[i];
vector<pii> ops;
F(b,0,20){
    int zeros=0;
    for(int x:a){
        if(!((x>>b)&1))zeros++;
    }
    F(i,0,zeros){
        if((a[i]>>b)&1){
            if(i+1<n){
                a[i+1]^=a[i];
                ops.pb(mp(i+2,i+1));
            }
        }
    }
    FR(i,n-1,zeros){
        if(!((a[i]>>b)&1)){
            if(i-1>=0){
                a[i-1]^=a[i];
                ops.pb(mp(i,i+1));
            }
        }
    }
}
cout<<ops.size()<<'\n';
for(auto &x:ops)cout<<x.fi<<' '<<x.se<<'\n';
}

signed main() {
    ios_base::sync_with_stdio(0);cin.tie(nullptr);
//    setIO(""");

    int tt=1;
   // cin>>tt;
    //cout<<fixed<<setprecision(20);
    while(tt--)solve();
    
    return 0;
}

Compilation message (stderr)

xorsort.cpp: In function 'void setIO(std::string)':
xorsort.cpp:10:54: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 | void setIO(string name = ""){if(name.size()){ freopen((name + ".in").c_str(), "r", stdin);freopen((name + ".out").c_str(), "w", stdout);}}
      |                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xorsort.cpp:10:98: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 | void setIO(string name = ""){if(name.size()){ freopen((name + ".in").c_str(), "r", stdin);freopen((name + ".out").c_str(), "w", stdout);}}
      |                                                                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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