Submission #977282

#	Time	Username	Problem	Language	Result	Execution time	Memory
977282		LOLOLO	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	6 ms	3104 KiB

ho_t2

#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
 
#define           f    first
#define           s    second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (int)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())
 
const int N = 2e5 + 100;
int pr[N], suff[N];

int main() {
    ios_base::sync_with_stdio(false); 
    cin.tie(NULL);
    cout.tie(NULL);

    vector <int> pos;
    deque <int> dq;
    int n, k;
    cin >> n >> k;

    string s;
    cin >> s;
    s = 'a' + s;
    
    for (int i = 1; i <= n; i++) {
        if (s[i] == 'O')
            pos.pb(i);

        pr[i] = -1;
        if (s[i] == 'J') {
            dq.push_back(i);
        }

        if (sz(dq) > k) {
            dq.pop_front();
        }

        if (sz(dq) == k) {
            pr[i] = dq.front();
        }
    }

    while (sz(dq))
        dq.pop_back();

    for (int i = n; i >= 1; i--) {
        suff[i] = -1;
        if (s[i] == 'I') {
            dq.push_back(i);
        }

        if (sz(dq) > k)
            dq.pop_front();

        if (sz(dq) == k) {
            suff[i] = dq.front();
        }
    }

    int ans = n + 1;
    for (int i = k - 1; i < sz(pos); i++) {
        int r = suff[pos[i]], l = pr[pos[i - k + 1]];
        if (r != -1 && l != -1) {
            ans = min(ans, r - l + 1 - k * 3);
        }
    }

    if (ans == n + 1)
        ans = -1;

    cout << ans << '\n';
    return 0;
}   

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