bzoj4636: 蒟蒻的数列

#include<cstdio>
#include<queue>
#include<algorithm>
struct heap{
    std::priority_queue<int>h,hd;
    inline void ins(int x){h.push(x);}
    inline void del(int x){hd.push(x);}
    inline int top(){
        while(!hd.empty()&&h.top()==hd.top())h.pop(),hd.pop();
        return h.top();
    }
}h;
struct event{
    int x,v,t;
}e[80010];
bool operator<(event a,event b){
    return a.x<b.x;
}
int n,p=0;
long long ans=0;
int main(){
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        e[p].x=a;
        e[p].t=1;
        e[p+1].x=b;
        e[p].v=e[p+1].v=c;
        p+=2;
    }
    e[p++]=(event){0,0,1};
    e[p++]=(event){1000000001,0,0};
    std::sort(e,e+p);
    int px=0,mx=0;
    e[p].x=-1;
    for(int i=0,j;i<p;i=j){
        j=i;
        while(e[j].x==e[i].x)++j;
        for(int k=i;k<j;k++)if(e[k].t)h.ins(e[k].v);else h.del(e[k].v);
        ans+=1ll*mx*(e[i].x-px);
        px=e[i].x;
        mx=h.top();
    }
    printf("%lld\n",ans);
    return 0;
}