Submission #201564

#	Time	Username	Problem	Language	Result	Execution time	Memory
201564		qkxwsm	JJOOII 2 (JOI20_ho_t2)	C++14	100 / 100	13 ms	2684 KiB

ho_t2

#include <bits/stdc++.h>

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
    if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
    if (a < b) a = b;
}

#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

const int MAXN = 200013;
const int INF = 1000000007;

int N, K;
int arr[MAXN];
vi pos[3];
int ans = INF;

int32_t main()
{
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(4);
    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> N >> K;
    string temps; cin >> temps;
    FOR(i, 0, N)
    {
        if (temps[i] == 'J') arr[i] = 0;
        if (temps[i] == 'O') arr[i] = 1;
        if (temps[i] == 'I') arr[i] = 2;
    }
    //when is it ok to start the I?
    //when is it ok to start the O?
    //when is it ok to start the J?
    FOR(i, 0, N)
    {
        pos[arr[i]].PB(i);
    }
    int it1 = 0, it2 = 0;
    for (int i = 0; i <= SZ(pos[0]) - K; i++)
    {
        while(it1 < SZ(pos[1]) && pos[1][it1] < pos[0][i + K - 1]) it1++;
        if (it1 + K - 1 >= SZ(pos[1])) break;
        while(it2 < SZ(pos[2]) && pos[2][it2] < pos[1][it1 + K - 1]) it2++;
        if (it2 + K - 1 >= SZ(pos[2])) break;
        int lo = pos[0][i], hi = pos[2][it2 + K - 1];
        ckmin(ans, hi - lo + 1 - 3 * K);
    }
    if (ans >= INF)
    {
        cout << "-1\n";
        return 0;
    }
    cout << ans << '\n';
    return 0;
}

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