bitset
1 #include<algorithm> 2 #include<iostream> 3 #include<cstdlib> 4 #include<cstring> 5 #include<cstdio> 6 #include<string> 7 #include<bitset> 8 #include<cmath> 9 #include<ctime> 10 #include<queue> 11 #include<stack> 12 #include<map> 13 #include<set> 14 #define rre(i,r,l) for(int i=(r);i>=(l);i--) 15 #define re(i,l,r) for(int i=(l);i<=(r);i++) 16 #define Clear(a,b) memset(a,b,sizeof(a)) 17 #define inout(x) printf("%d",(x)) 18 #define douin(x) scanf("%lf",&x) 19 #define strin(x) scanf("%s",(x)) 20 #define LLin(x) scanf("%lld",&x) 21 #define op operator 22 #define CSC main 23 typedef unsigned long long ULL; 24 typedef const int cint; 25 typedef long long LL; 26 using namespace std; 27 void inin(int &ret) 28 { 29 ret=0;int f=0;char ch=getchar(); 30 while(ch<'0'||ch>'9'){if(ch=='-')f=1;ch=getchar();} 31 while(ch>='0'&&ch<='9')ret*=10,ret+=ch-'0',ch=getchar(); 32 ret=f?-ret:ret; 33 } 34 int n,sum,ans; 35 bitset<2000020> a; 36 int main() 37 { 38 cin>>n;a[0]=1; 39 re(i,1,n) 40 { 41 int x;cin>>x; 42 sum+=x; 43 a^=a<<x; 44 } 45 re(i,1,sum)if(a[i])ans^=i; 46 cout<<ans; 47 return 0; 48 }