acwing298 围栏

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
 const int N=16e3+3,M=102;
 int n,m,f[N][N];
 int hh,tt,q[N];
 
 struct T{
     int c,L,p;
     bool operator<(T &u)const{
         return p<u.p;
     }
 }a[N];
 int func(int i,int k){
     return f[i-1][k]-k*a[i].c;
 }
 void solve(){
     int i,j;
     
     for(i=1;i<=n;i++){
         hh=tt=0;
         for(j=0;j<=m;j++){
              f[i][j]=max(f[i-1][j],f[i][j-1]);

              if(j>=a[i].p){
                  while(hh<=tt&&q[hh]<j-a[i].L) hh++;
                  if(hh<=tt) 
                  f[i][j]=max(f[i][j],func(i,q[hh])+a[i].c*j);
              }
            else{
                while(hh<=tt&&func(i,j)>func(i,q[tt])) tt--;
                q[++tt]=j;    
            }      
        } 
     }
     cout<<f[n][m]<<endl;
 }
 int main(){
     int i,j;
     cin>>m>>n;
     for(i=1;i<=n;i++) cin>>a[i].L>>a[i].c>>a[i].p;
     sort(a+1,a+1+n);
     solve();
 }