NEFU 1266 快乐的雨季 (线段树)

题意：

中文

思路：

线段树基础题当然亦可以分块做

代码：

线段树：

#include <bits/stdc++.h>using namespace std;#define ls l,mid,rt*2#define rs mid+1,r,rt*2+1#define mi (l+r)/2const int MAXN=1e5+7;int n,m;long long sum[MAXN*4];int lazy[MAXN*4],st,en,v;void push_down(int l,int r,int rt){    if(lazy[rt]){        int mid=mi;        lazy[rt*2+1]+=lazy[rt];        lazy[rt*2]+=lazy[rt];        sum[rt*2+1]+=(long long)lazy[rt]*(r-mid);        sum[rt*2]+=(long long)lazy[rt]*(mid-l+1);        lazy[rt]=0;    }}void push_up(int rt){    sum[rt]=sum[rt*2]+sum[rt*2+1];}void build(int l,int r,int rt){    sum[rt]=lazy[rt]=0;    if(l==r){        return ;    }    int mid=mi;    build(ls);    build(rs);}long long update_and_query(int l,int r,int rt){    if(r<st||l>en) return 0;    if(st<=l&&r<=en){        lazy[rt]+=v;        sum[rt]+=(long long)v*(r-l+1);        return sum[rt];    }    push_down(l,r,rt);    int mid=mi;    long long ans=update_and_query(ls)+update_and_query(rs);    push_up(rt);    return ans;}int main(){    freopen("data.in","r",stdin);    freopen("out.txt","w",stdout);    while(scanf("%d%d",&n,&m)!=-1){        build(1,n,1);        while(m--){scanf("%d%d%d",&st,&en,&v);            printf("%lld\n",update_and_query(1,n,1));        }    }}

分块：

#include <iostream>#include <queue>#include <cstdio>#include <algorithm>#include <cmath>using namespace std;const int MAXN=1e5+7;int n,m;int blen,belong[MAXN],r[MAXN],l[MAXN],num;long long sum[MAXN],a[MAXN];int lazy[MAXN];void build(){    blen=sqrt(n);    num=n/blen;    if(n%blen) n++;    for(int i=1;i<=num;i++) l[i]=blen*(i-1)+1,r[i]=blen*i;    r[num]=n;    for(int i=1;i<=num;i++){        sum[i]=lazy[i]=0;        for(int j=l[i];j<=r[i];j++){            belong[j]=i;            a[j]=0;        }    }}long long update_and_query(int st,int en,int v){    long long ans=0;    if(belong[st]==belong[en]){        for(int i=st;i<=en;i++){            a[i]+=v;            ans+=a[i]+lazy[belong[st]];        }        sum[belong[st]]+=(long long)v*(en-st+1);    }else{        for(int i=st;i<=r[belong[st]];i++){            a[i]+=v;            ans+=a[i]+lazy[belong[st]];        }        sum[belong[st]]+=(long long)v*(r[belong[st]]-st+1);        for(int i=belong[st]+1;i<belong[en];i++){            sum[i]+=(long long)v*(r[i]-l[i]+1);            lazy[i]+=v;            ans+=sum[i];        }        for(int i=l[belong[en]];i<=en;i++){            a[i]+=v;            ans+=a[i]+lazy[belong[en]];        }        sum[belong[en]]+=(long long)v*(en-l[belong[en]]+1);    }    return ans;}int main(){    //freopen("data.in","r",stdin);    //freopen("out.txt","w",stdout);    while(scanf("%d%d",&n,&m)!=-1){        build();        while(m--){int st,en,v;            scanf("%d%d%d",&st,&en,&v);            printf("%lld\n",update_and_query(st,en,v));        }    }}