Submission #74004247

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
using i128 = __int128;
using pii = pair<int, int>;
#define cty cout<<"Yes"<<endl
#define ctn cout<<"No"<<endl
#define dbg(x) cout<<#x<<" : "<<x<<endl
#define endl '\n'
#define int long long
const int mxn = 5e5+10;
const int mod = 998244353;
int n,p;
int a[mxn];
void LonelyLunar_solve(){
	cin>>n>>p;
	for(int i = 1;i <= n; i++){
		cin>>a[i];
	}
	// left r
	// right r+1
	int l = 1,r = n;
	while(l<=n&&a[l]==1)l++;
	while(r>=1&&a[r]==1)r--;
	//l-p
	if(l>r){
		cout<<"0\n";
		return;
	}
	int res = 0;
	if(p<l) l = p+1;
	else if(p>r) r = p;
	for(int i = l;i <= r; i++){
		res+=(a[i]==1);
	}
	res+=(r-l+1);
	cout<<res<<endl;
}
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int _ = 1;
	// cin>>_;
	while(_--){
		LonelyLunar_solve();
	}
	return 0;
}

Submission Info

Judge Result