【分块】BZOJ4216 Pig

题面在这里

典型的分块题……

没什么好说的，直接分块搞就好了

示例程序：

#include<cstdio>#include<cmath>#include<algorithm>#define _abs(x) ((x)<0?-(x):(x))#define LL long longusing namespace std;const int maxn=500005;int n,q,t,a[maxn],blk;LL sum[710];int main(){    scanf("%d%d%d",&n,&q,&t);    blk=sqrt(n);    for (int i=1;i<=n;i++)     scanf("%d",&a[i]),sum[i/blk]+=a[i];    LL lastans=0;    for (int i=1;i<=q;i++){        int l,r;scanf("%d%d",&l,&r);        if (t==1){            l=(l^_abs(lastans))%n+1;            r=(r^_abs(lastans))%n+1;            if (l>r) swap(l,r);        }        int bl=l/blk,br=r/blk;LL ans=0;        if (bl==br){            for (int j=l;j<=r;j++) ans+=a[j];        }else{            for (int j=l,tj=(bl+1)*blk;j<tj;j++) ans+=a[j];            for (int j=br*blk;j<=r;j++) ans+=a[j];            for (int j=bl+1;j<br;j++) ans+=sum[j];        }        printf("%lld\n",ans);lastans=ans;    }    return 0;}