cdoj1324暴力分块

Posted 2020-08-23 狡啮之仰

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;
typedef long long ll;
const int maxn=1e5+7;
int belong[maxn],l[maxn],r[maxn],block,num,n,q;
ll a[maxn],Max[maxn];
void build(){
    block=sqrt(n);
    num=n/block;if(n%block!=0) num++;
    for(int i=1;i<=num;++i){//num 不要写成n
        l[i]=(i-1)*block+1;r[i]=i*block;
    }
    r[num]=n;//收敛
    for(int i=1;i<=n;++i){
        belong[i]=(i-1)/block+1;
    }
    for(int i=1;i<=n;++i){
        Max[belong[i]]=max(Max[belong[i]],a[i]);
    }
}
void update(int x,int y){//单点更新
    a[x]+=y;
    Max[belong[x]]=max(Max[belong[x]],a[x]);
}
ll ask(int x,int y){
    //变量与数组重名
    ll ans=-1;
    if(belong[x]==belong[y]){
        for(int i=x;i<=y;++i){
            ans=max(ans,a[i]);
        }
        return ans;
    }
    for(int i=x;i<=r[belong[x]];++i){
        ans=max(ans,a[i]);
    }
    for(int i=belong[x]+1;i<belong[y];++i){
        ans=max(ans,Max[i]);
    }
    for(int i=l[belong[y]];i<=y;++i){
        ans=max(ans,a[i]);
    }
    return ans;
}
int main(){
    scanf("%d%d",&n,&q);
    build();
    int i,t,x,y;
    for(i=0;i<q;++i){
        scanf("%d%d%d",&t,&x,&y);
        if(t==1){
            update(x,y);
        }
        else{
            printf("%lld\n",ask(x,y));
        }
    }
    return 0;
}