Submission #48550

#	Time	Username	Problem	Language	Result	Execution time	Memory
48550		Pajaraja	XOR Sum (info1cup17_xorsum)	C++17	100 / 100	935 ms	37680 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;
int a[1000007],c[1000007];
int main()
{
	int n,sol=0;
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%d",&a[i]);
	for(int j=0;j<31;j++)
	{
		int b=(1<<j),t=0;
		long long bc=0;
		if(j) for(int i=1;i<=n;i++) if((a[i] | (1<<(j-1)))!=a[i]) c[++t]=a[i];
		if(j) for(int i=1;i<=n;i++) if((a[i] | (1<<(j-1)))==a[i]) c[++t]=a[i];
		if(j) for(int i=1;i<=n;i++) {a[i]=c[i]; c[i]=a[i]%b;} 
		for(int i=1;i<=n;i++) if((a[i] | b) == a[i]) bc++;
		long long k=0;
		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+bc*(n-bc))%2==1) sol+=b;
	}
	printf("%d",sol);
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
xorsum.cpp:8:29: 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: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 38 / 38
• Subtask 5: 23 / 23