Submission #1139152

#	Time	Username	Problem	Language	Result	Execution time	Memory
1139152		KasymK	XOR Sum (info1cup17_xorsum)	C++20	100 / 100	593 ms	8240 KiB

xorsum

#include "bits/stdc++.h"
using namespace std;
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define tr(i, c) for(auto i = c.begin(); i != c.end(); ++i)
#define wr puts("----------------")
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
const int N = 1e6+5;
int v[N], A[N];

int main(){
	int n, answer=0;
	scanf("%d", &n);
	for(int i = 1; i <= n; ++i)
		scanf("%d", v+i);
	for(int j = 0; j <= 30; ++j){
		int sm=0, op=0, ad=0;
		if(j){
			for(int i = 1; i <= n; ++i)
				if(!(v[i]>>(j-1)&1))
					A[++op]=v[i];
		}
		if(j){
			for(int i = 1; i <= n; ++i)
				if(v[i]>>(j-1)&1)
					A[++op]=v[i];
		}
		if(j){
			for(int i = 1; i <= n; ++i)
				v[i]=A[i], A[i]=v[i]%(1<<j);
		}
		for(int i = 1; i <= n; ++i)
			sm+=(!(v[i]>>j&1));
		int id1=1, id2=n;
		while(id1<=n){
			while(A[id1]+A[id2]>=(1<<j))
				id2--;
			ad+=(n-id2), id1++;
		}
		for(int i = 1; i <= n; ++i)
			ad+=(A[i]>=((1<<j)>>1));
		int f=ad/2+sm*(n-sm);
		if(f&1)
			answer+=(1<<j);
	}
	printf("%d\n", answer);
	return 0;
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:20:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         scanf("%d", &n);
      |         ~~~~~^~~~~~~~~~
xorsum.cpp:22:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |                 scanf("%d", v+i);
      |                 ~~~~~^~~~~~~~~~~

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