Submission #48395

#	Time	Username	Problem	Language	Result	Execution time	Memory
48395		Pajaraja	XOR Sum (info1cup17_xorsum)	C++17	0 / 100	2 ms	548 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;
int a[1000007],c[1000007];

int main()
{
	int n,sol=0;
	freopen("tc.txt","r",stdin);
	freopen("out.txt","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%d",&a[i]);
	for(int j=0;j<30;j++)
	{
		int b=(1<<j),bc=0;
		for(int i=1;i<=n;i++) c[i]=a[i]%b;
		for(int i=1;i<=n;i++) if((a[i] | b) == a[i]) bc++;
		long long k=2*bc*(n-bc); 
		sort(c+1,c+n+1);
		int t1=1,t2=n;
		while(t1<=n)
		{
			while(c[t2]+c[t1]>=b) t2--;
			k+=(n-t2);
			t1++;
		}
		for(int i=1;i<=n;i++) if(2*c[i]>=b) k++;
		if((k/2)%2==1) sol+=b;
	}
	printf("%d",sol);
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:8:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("tc.txt","r",stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~
xorsum.cpp:9:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("out.txt","w",stdout);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
xorsum.cpp:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
xorsum.cpp:11:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++) scanf("%d",&a[i]);
                        ~~~~~^~~~~~~~~~~~

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