Submission #953496

#	Time	Username	Problem	Language	Result	Execution time	Memory
953496		Angus_Yeung	JJOOII 2 (JOI20_ho_t2)	C++17	0 / 100	0 ms	348 KiB

ho_t2

#include <bits/stdc++.h>
#define x first
#define y second
#define pii pair<ll, ll>
typedef long long ll;
const ll MOD = 1000000007LL;
const ll INF = 1e15;
using namespace std;

ll n, k, cnt, pos[5], tmp1, tmp2;
char a[200010];

int main() {
	cin.tie(0); cout.tie(0);
	ios::sync_with_stdio(0);
	
	cin >> n >> k;
	for (int i = 1; i <= n; i++) cin >> a[i];
	
	pos[1] = n+1;
	pos[3] = 0;
	
	cnt = 0;
	for (int i = 1; i <= n; i++) {
		cnt += (a[i] == 'J');
		if (cnt == k) {
			pos[1] = i;
			break;
		}
	}
	
	cnt = 0;
	for (int i = n; i >= 1; i--) {
		cnt += (a[i] == 'I');
		if (cnt == k) {
			pos[3] = i;
			break;
		}
	}
	
	cnt = 0;
	for (int i = pos[1]+1; i <= pos[3]-1; i++) {
		cnt += (a[i] == 'O');
	}
	
	tmp1 = 0;
	while (tmp1 < n && a[tmp1+1] != 'J') tmp1++;
	tmp2 = n+1;
	while (tmp2 > 1 && a[tmp2-1] != 'I') tmp2--;
	
	if (cnt >= k) {
		cout << tmp1+n-tmp2+1 << "\n";
	}
	else cout << "-1\n";
	
	return 0;
}
/*



*/

• Subtask 1: 0 / 1
• Subtask 2: 0 / 12
• Subtask 3: 0 / 87