P1719 Let‘s play a game!

#include<bits/stdc++.h>
using namespace std;
int n,k;
int x[31];
int check(int b)
{
	int s = upper_bound(x , x + 30 , b) - x; //返回的是数组下标 
	return b-x[s-1];
}
int main()
{
	cin>>n>>k;
	int *a = new int[n+1];
	int l=1;
	for(int i=0;i<=30;i++) { //2的次幂打表
		x[i] = l;
		l*=2;
	}
	int ans = 0;
	for(int i=1;i<=n;i++) {
		cin>>a[i];
		if(a[i]==k) {
			int s = check(i);
			if(s<=ans) ans++;
			else ans += s-ans+1; 
		}
	}
	cout<<ans<<endl;
}