[LOJ] 分块九题 1

https://loj.ac/problem/6277

区间修改，单点查询。

//Stay foolish,stay hungry,stay young,stay simple
#include<iostream>
#include<cstdio>
#include<cctype>
#include<cmath>
using namespace std;

const int MAXN=500005;

inline int read_d(){
    int ret=0,f=1;char c;
    while(c=getchar(),!isdigit(c)) f=(c=='-')?-1:1;
    while(isdigit(c)){
        ret=ret*10+c-'0';
        c=getchar();
    }
    return f*ret;
}

int n,m;

int block,num;
int a[MAXN];
int l[MAXN],r[MAXN],bl[MAXN],inc[MAXN];

void build(){
    block=sqrt(n);
    num=n/block;
    if(n%block) num++;
    for(int i=1;i<=num;i++){
        l[i]=(i-1)*block+1;
        r[i]=i*block;
    }
    for(int i=1;i<=n;i++)
        bl[i]=(i-1)/block+1;
    r[num]=n;
}

void updata(int x,int y,int w){
    if(bl[x]==bl[y]){
        for(int i=x;i<=y;i++) a[i]+=w;
        return ;
    }
    for(int i=x;i<=r[bl[x]];i++)
        a[i]+=w;
    for(int i=bl[x]+1;i<=bl[y]-1;i++)
        inc[i]+=w;
    for(int i=l[bl[y]];i<=y;i++)
        a[i]+=w;
}

inline int query(int x){
    return a[x]+inc[bl[x]];
}

int main(){
    n=read_d();m=n;
    for(int i=1;i<=n;i++)
        a[i]=read_d();
    build();
    for(int i=1;i<=m;i++){
        int x,y,z,q;
        q=read_d();x=read_d();
        y=read_d();z=read_d();
        if(q==0) updata(x,y,z);
        else printf("%d\n",query(y));
    }
    return 0;
}