hiho1080 - 数据结构 线段树(入门题，两个lazy tag)

题目链接

维护区间和，两个操作：一个是将某个区间设置成一个值，一个是将某个区间增加一个固定值

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每走到一个区间就把lazy tag下放。下放的时候注意顺序！

#include <cstdio>
#include <cstring>
const int N = ;
struct NODE{
     int l,r;
     int sum;
     int setTo,add;
     NODE(){setTo=add=;}
     int length(){return (r-l+);}
};
int data[N];
NODE segtree[N*];

void build(int id,int l,int r){
     segtree[id].l = l;
     segtree[id].r = r;
     if(l==r){
        segtree[id].sum = data[l];
        return ;
     }
     int mid = (l+r)>>;
     build(id*+,l,mid);
     build(id*+,mid+,r);
     segtree[id].sum = segtree[id*+].sum+segtree[id*+].sum;
}

void modify(int id,int spos,int epos,int value,int type){
     if(segtree[id].l==spos&&segtree[id].r==epos){
        if(type){
            segtree[id].setTo = value;
            segtree[id].add = ;
            segtree[id].sum = segtree[id].length()*value;
        }
        else{
            segtree[id].add += value;
            segtree[id].sum += segtree[id].length()*value;
        }
        return ;
     }

     //push down
     if(segtree[id].setTo){
        segtree[id*+].setTo=segtree[id*+].setTo=segtree[id].setTo;
        segtree[id*+].add=segtree[id*+].add=;
        segtree[id*+].sum = segtree[id*+].length()*segtree[id*+].setTo;
        segtree[id*+].sum = segtree[id*+].length()*segtree[id*+].setTo;
        segtree[id].setTo = ;
     }
     if(segtree[id].add){
        segtree[id*+].add += segtree[id].add;
        segtree[id*+].add += segtree[id].add;
        segtree[id*+].sum += segtree[id*+].length()*segtree[id].add;
        segtree[id*+].sum += segtree[id*+].length()*segtree[id].add;
        segtree[id].add = ;
     }

     int mid = (segtree[id].l+segtree[id].r)>>;
     if(epos<=mid) modify(id*,spos,epos,value,type);
     else if(spos>mid) modify(id*+,spos,epos,value,type);
     else{
        modify(id*+,spos,mid,value,type);
        modify(id*+,mid+,epos,value,type);
     }

     segtree[id].sum = segtree[id*+].sum+segtree[id*+].sum;
}
int main(){
    int n,t;
    scanf("%d%d",&n,&t); n++;
    for(int i=;i<=n;i++) scanf("%d",data+i);
    build(,,n);
    while(t--){
        int a,b,c,d;
        scanf("%d%d%d%d",&a,&b,&c,&d);
        modify(,b+,c+,d,a);
        printf("%d\n",segtree[].sum);
    }
    return ;
}