Educational Codeforces Round 27 D. Driving Test

单调栈

题意看了半天。。。

     #include <cstdio>
     #include <cstdlib>
     #include <cmath>
     #include <cstring>
     #include <string>
     #include <algorithm>
     #include <iostream>
     using namespace std;
     #define ll long long
 
     const int maxn=2e5+;
     const int inf=1e9;
 
     int sum1,tot1;
     int f[maxn],g;
 
     int main()
     {
         int n,a,b,i,j,v;
         scanf("%d",&n);
         for (i=;i<=n;i++)
         {
             scanf("%d",&a);
             if (a== || a==)
                 scanf("%d",&b);
 
             if (a==)
                 tot1=;
             else if (a==)
                 tot1++;
             else if (a==)
                 sum1+=tot1,tot1=;
 
             if (a==)
                 g=;
             else if (a==)
             {
                 v=b;
                 while (g> && f[g]<v)
                     g--,sum1++;
             }
             else if (a==)
             {
                 if (b<v)
                     sum1++;
                 else
                     f[++g]=b;
             }
         }
         printf("%d",sum1);
         return ;
     }