洛谷 P2376 [USACO09OCT]津贴Allowance

https://www.luogu.org/problemnew/show/P2376

看了题解做的，根本不会贪心。。

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<vector>
 using namespace std;
 #define fi first
 #define se second
 #define mp make_pair
 #define pb push_back
 typedef long long ll;
 typedef unsigned long long ull;
 typedef pair<int,int> pii;
 int n,c;
 int ans;
 pii t1[];
 int len;
 int main()
 {
     int t,i,x,y,s;
     bool fl;
     scanf("%d%d",&n,&c);
     for(i=;i<=n;i++)
     {
         scanf("%d%d",&x,&y);
         if(x>=c)    ans+=y;
         else    t1[++len]=mp(x,y);
     }
     sort(t1+,t1+len+);
     while()
     {
         fl=;
         for(i=;i<=len;i++)
             if(t1[i].se!=)
                 fl=;
         if(!fl)    break;
         s=;
         for(i=len;i>=;i--)
         {
             t=min(t1[i].se,(c-s)/t1[i].fi);
             s+=t1[i].fi*t;
             t1[i].se-=t;
         }
         if(s<c)
         {
             fl=;
             for(i=;i<=len;i++)
                 if(t1[i].se!=)
                     fl=;
             if(!fl)    break;
             for(i=;i<=len;i++)
                 if(t1[i].se)
                 {
                     --t1[i].se;
                     break;
                 }
         }
         ans++;
     }
     printf("%d",ans);
     return ;
 }