Bear and Finding Criminals

B. Bear and Finding Criminals-codeforces

// working.cpp by Bill Weinman <http://bw.org/>
#include <bits/stdc++.h>
using namespace std;
int main() {
	    int n,in;
	    cin>>n>>in;
	    int a[n];
	    for (int i=1;i<=n;i++)
	        cin>>a[i];
	    int ans=0;
	    int l=in-1,r=in+1;
	    while(l>=1&&r<=n)
	    {
	        if (a[l]==1&&a[r]==1)
	        {
	            ans+=2;
	        }
	        l--,r++;
	    }
	    if (l==0)
	    {
	        for (int i=r;i<=n;i++)
	        {
	            if (a[i]==1)
	                ans++;
	        }
	    }
	    if (r==n+1)
	    {
	        for (int i=l;i>=0;i--)
	        {
	            if (a[i]==1)
	                ans++;
	        }
	    }
	    if (a[in]==1)
	        ans++;
	    cout<<ans<<endl;
    return 0;
}