> 两个代码，一个ac，一个wa，用cin ac，用scanf就wa
> #include<stdio.h>
> #include<iostream>
> using namespace std;
> 
> int stack[50010],top;
> int main()
> {
> 	int n,t,i,j,x,y,ans;
> 	scanf("%d%d",&n,&t);//换成cin>>n>>t;
> 	top=ans=0;
> 	for(i=0;i<n;i++)
> 	{
> 		scanf("%d%d",&x,&y);//换成cin>>x>>y;
> 		if(y<stack[top-1])
> 		{
> 			while(y<stack[top-1])
> 			{
> 				top--;
> 			}			
> 		}
> 		if(y>stack[top-1]&&y!=0||top==0&&y!=0) {stack[top++]=y;ans++;}
> 	}
> 	printf("%d",ans);
> }
> 
>