Submission #1097106

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097106		TrinhKhanhDung	JJOOII 2 (JOI20_ho_t2)	C++14	100 / 100	6 ms	2424 KiB

ho_t2

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18 + 10
#define INF (ll)1e9
#define MOD (ll)(998244353)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 2e5 + 10;

int N, K;
string s;
int prefix[MAX], suffix[MAX];

void solve(){
    cin >> N >> K >> s;
    s = "*" + s + "*";

    int j = 0, cnt = 0;
    for(int i = 1; i <= N; i++){
        cnt += (s[i] == 'J');
        while(cnt > K || (cnt == K && s[j] != 'J')){
            cnt -= (s[j] == 'J');
            j++;
        }
        if(cnt == K) prefix[i] = j;
    }

    j = N + 1;
    cnt = 0;
    for(int i = N; i >= 1; i--){
        cnt += (s[i] == 'I');
        while(cnt > K || (cnt == K && s[j] != 'I')){
            cnt -= (s[j] == 'I');
            j--;
        }
        if(cnt == K) suffix[i] = j;
    }

    j = cnt = 0;
    int ans = INF;
    for(int i = 1; i < N; i++){
        cnt += (s[i] == 'O');
        while(cnt > K || (cnt == K && s[j] != 'O')){
            cnt -= (s[j] == 'O');
            j++;
        }
        if(cnt == K && prefix[j - 1] != 0 && suffix[i + 1] != 0){
            minimize(ans, suffix[i + 1] - prefix[j - 1] + 1 - 3 * K);
        }
    }

    cout << (ans >= INF ? -1 : ans) << '\n';
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//    freopen("task.inp","r",stdin);
//    freopen("task.out","w",stdout);

    int T = 1;
//    cin >> T;
    for(; T; T--) solve();

    return 0;
}

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