Submission #67695

#	Time	Username	Problem	Language	Result	Execution time	Memory
67695		yusufake	XOR Sum (info1cup17_xorsum)	C++98	45 / 100	1672 ms	13620 KiB

xorsum

#include<bits/stdc++.h>
using namespace std;

#define mp make_pair
#define pb push_back
#define st first
#define nd second

typedef long long ll;
typedef pair < int , int > pp;
typedef vector < int > vi;

const int mod = 1e9 + 7;
const int N   = 1e6 + 6;

int T[N],A[N],one[N],o,zer[N],z,n,i,j,x,ans;
ll t;
int main (){
    scanf("%d",&n);
    for(i=1;i<=n;i++){
        scanf("%d",&A[i]);
    }
   
    for(j=0;j<31;j++){    
        
        z = o = 0;
        for(i=1;i<=n;i++){
            x = A[i];
            if(x & (1<<j)){
                one[++o] = T[i];                
            }
            else{
                zer[++z] = T[i];
            }
        }
        
        sort(zer+1 , zer+z+1);
        sort(one+1 , one+o+1);
        t = 0;
        for(i=1;i<=n;i++){
            x = A[i];
            if(x & (1<<j)){
                t += o+1 - (int)(lower_bound(one+1 , one+o+1 , (1<<j)-T[i]) - one);
                t += (int)(lower_bound(zer+1 , zer+z+1 , (1<<j)-T[i]) - zer-1);
            }
            else{
                t += z+1 - (int)(lower_bound(zer+1 , zer+z+1 , (1<<j)-T[i]) - zer);
                t += (int)(lower_bound(one+1 , one+o+1 , (1<<j)-T[i]) - one-1);
            }
        }

        for(i=1;i<=n;i++)
            if((A[i]+A[i]) & (1<<j))
                t++;
        
        if(t&1) assert(0);
        t >>= 1;
        if(t&1)
            ans += 1 << j;
        
        for(i=1;i<=n;i++)
            T[i] += A[i] & (1 << j);
    
    }
    
    printf("%d",ans);
    return 0;
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:19:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
xorsum.cpp:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&A[i]);
         ~~~~~^~~~~~~~~~~~

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