前后断开即可

#include<bits/stdc++.h>
using namespace std;
int i,n,f0,m,f[1000001],shu[1000001],oooo;
int find(int l,int r,int a) 
{  int p;
	while(r-l>1){
		p=(r+l)/2;	
		if(f[p]==a) return p;
        if(f[p]>a) r=p;
			else l=p;
	}
	return r;
}
int main(){
	freopen("listwo.in","r",stdin);
	freopen("listwo.out","w",stdout);
    scanf("%d%d",&n,&m);
    for( i=1;i<=n;i++)cin>>shu[i];
    for(i=1;i<m;i++) 
    	if(shu[i]<=shu[m]){
    	if(shu[i]>f[f0]){
    		f0++;
    		f[f0]=shu[i];
		}
		else f[find(0,f0,shu[i])]=shu[i];
	}
	oooo=f0;
	f0=0;
	memset(f,0,sizeof(f));
	for(i=m+1;i<=n;i++) 
	if(shu[i]>=shu[m]){
    	if(shu[i]>f[f0]){
    		f0++;
    		f[f0]=shu[i];
		}
		else f[find(0,f0,shu[i])]=shu[i];
	}
    printf("%d",f0+oooo+1);
    return 0;
}