HDU 4027 单点更新+“剪枝”

可以看出一个数开方大于等于7次时就一直为1了，利用这点剪枝

#include<cstdio>#include<cstring>#include<cmath>typedef long long ll;ll num[100010];struct Tree{    int l,r;    ll sum;}tree[400000];void build(int s,int t,int id){    tree[id].l=s;    tree[id].r=t;    if(s==t){        tree[id].sum=num[s];        return ;    }    int mid=(tree[id].l+tree[id].r)>>1;    build(s,mid,id<<1);    build(mid+1,t,(id<<1)+1);    tree[id].sum=tree[id<<1].sum+tree[(id<<1)+1].sum;}void update(int s,int t,int id){    if(tree[id].r-tree[id].l+1==tree[id].sum)    ///        return ;    if(tree[id].l==tree[id].r){        tree[id].sum=(int)sqrt(tree[id].sum);        return ;    }    int mid=(tree[id].l+tree[id].r)>>1;    if(t<=mid)        update(s,t,id<<1);    else if(mid<s)        update(s,t,(id<<1)+1);    else{        update(s,mid,id<<1);        update(mid+1,t,(id<<1)+1);    }    tree[id].sum=tree[id<<1].sum+tree[(id<<1)+1].sum;}ll query(int s,int t,int id){    if(tree[id].r-tree[id].l+1==tree[id].sum)          ///        return t-s+1;    if(tree[id].l==s && tree[id].r==t)        return tree[id].sum;    int mid=(tree[id].l+tree[id].r)>>1;    if(t<=mid)        return query(s,t,id<<1);    else if(mid<s)        return query(s,t,(id<<1)+1);    else        return query(s,mid,id<<1)+query(mid+1,t,(id<<1)+1);}int main(){    int i,n,m,whi,s,t,cas=0;    while(scanf("%d",&n)!=EOF){        printf("Case #%d:\n",++cas);        for(i=1;i<=n;i++)            scanf("%I64d",&num[i]);        build(1,n,1);        scanf("%d",&m);        for(i=1;i<=m;i++){            scanf("%d %d %d",&whi,&s,&t);            if(s>t){                int tem=t;                t=s;                s=tem;            }            if(whi==0)                update(s,t,1);            else                printf("%I64d\n",query(s,t,1));        }        printf("\n");    }}