洛谷P2947 [USACO09MAR]向右看齐Look Up

 #include<cstdio>
 #include<algorithm>
 #include<stack>
 #include<cctype>
 using namespace std;
 struct cow{
     int id;
     int data;
     cow(int id=,int data=):id(id),data(data){
     }
 }ans[];
 stack<cow> q;
 int n,tmp,cnt;
 inline bool cmp(const cow &a,const cow &b)
 {
     return a.id<b.id;
 }
 int main()
 {
     scanf("%d",&n);
     for(int i=;i<=n;i++)
     {
         scanf("%d",&tmp);
         while(!q.empty()&&q.top().data<tmp)
         {
             ans[++cnt]=q.top();
             ans[cnt].data=i;
             q.pop();
         }
         q.push(cow(i,tmp));
     }
     while(!q.empty())
     {
         ans[++cnt]=q.top();
         ans[cnt].data=;
         q.pop();
     }
     sort(ans+,ans++n,cmp);
     for(int i=;i<=n;i++) printf("%d\n",ans[i].data);
     return ;
 }