CF1137E Train Car Selection（单调栈维护凸函数）

#include<bits/stdc++.h>
using namespace std;
const int N=3e5+7;
#define int long long
typedef pair<int,int>pii;
int n,k,b,Q,top;
pii st[N];
long double getk(pii a,pii b){return 1.0*(b.second-a.second)/(a.first-b.first);}
int calc(pii a){return(a.first-1)*k+a.second+b;}
signed main()
{
    scanf("%lld%lld",&n,&Q);
    st[top=1]=pii(1,0);
    while(Q--)
    {
        int op,x,y;scanf("%lld%lld",&op,&x);
        if(op==1)st[top=1]=pii(1,0),k=b=0,n+=x;
        else if(op==2)
        {
            pii u=pii(n+1,-calc(pii(n+1,0)));
            while(top>1&&getk(u,st[top])>=getk(st[top],st[top-1]))--top;
            st[++top]=u,n+=x;
        }
        else scanf("%lld",&y),b+=x,k+=y;
        while(top>1&&calc(st[top])>=calc(st[top-1]))--top;
        printf("%lld %lld\n",st[top].first,calc(st[top]));
    }
}