Submission #496767

#	Time	Username	Problem	Language	Result	Execution time	Memory
496767		Nalrimet	XOR Sum (info1cup17_xorsum)	C++17	18 / 100	1689 ms	57520 KiB

xorsum

#include<bits/stdc++.h>

#pragma GCC optimization("g", on)
//#pragma GCC optimize ("inline")
//#pragma GCC optimization("03")
//#pragma GCC optimization("unroll-loops")
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popused,abm,mmx,avx,tune=native")
using namespace std;

const int N = 1e6 + 5;
const long long inf = 1000000000;
#define ll long long

#define F first
#define S second
#define pb push_back

int n, x[N];
map<int, bool> used;
map<int, int> cnt;
vector<int> v;
long long res, f;

 main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n;

    for(int i = 1; i <= n; ++i){
        cin >> x[i];
        if(n > 1e5){
            used[x[i]] = !used[x[i]];
            cnt[x[i]]++;
        }
    }
    if(n > 1e5){
        for(int i = 1; i <= n; ++i){
            if(cnt[x[i]]) {
                f = cnt[x[i]];
                if(f * (f - 1) / 2 % 2 == 1) res ^= x[i] + x[i];
                cnt[x[i]] = 0;
            }
            if(used[x[i]]) {
                v.pb(x[i]);
                used[x[i]] = 0;
            }
        }
    }
    else{
        for(int i = 1; i <= n; ++i){
            v.pb(x[i]);
        }
    }

    for(int i = 0; i < v.size(); ++i){
        for(int j = i; j < v.size(); ++j){
            res ^= v[i] + v[j];
        }
    }

    cout << res;

}

Compilation message (stderr)

xorsum.cpp:3: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    3 | #pragma GCC optimization("g", on)
      | 
xorsum.cpp:26:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   26 |  main() {
      |  ^~~~
xorsum.cpp: In function 'int main()':
xorsum.cpp:60:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for(int i = 0; i < v.size(); ++i){
      |                    ~~^~~~~~~~~~
xorsum.cpp:61:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |         for(int j = i; j < v.size(); ++j){
      |                        ~~^~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 38
• Subtask 5: 0 / 23