loj 10001 种树

*********贪心，把需要的路段终止点排序，然后在每个区间内判断是否已经满足条件，不满足的从区间右端向左端种树。

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<cmath>
 using namespace std;
 int i,j,n,h,vis[] = {},ans = ,tot;
 struct node
 {
     int b;
     int e;
     int t;
 }a[];
 int cmp(node a,node b)
 {
     return a.e < b.e;
 }
 int main()
 {
     scanf("%d",&n);
     scanf("%d",&h);
     for(i = ;i <= h;i++)
     {
         scanf("%d %d %d",&a[i].b,&a[i].e,&a[i].t);
     }
     sort(a + ,a +  + h,cmp);
     for(i = ;i <= h;i++)
     {
         tot = ;
         for(j = a[i].b;j <= a[i].e;j++)
         {
             if(vis[j] == )
             {
                 tot++;
             }
             if(tot == a[i].t)
             break;
         }
         if(tot < a[i].t)
         {
             for(j = a[i].e;j >= a[i].b;j--)
             {
                 if(vis[j] == )
                 {
                     vis[j] = ;
                     tot++;
                     ans++;
                 }
                 if(tot == a[i].t)
                 break;
             }
         }
     }
     printf("%d",ans);
     return ;
 }