Submission #1257235

#	Time	Username	Problem	Language	Result	Execution time	Memory
1257235		goulthen	JJOOII 2 (JOI20_ho_t2)	C++20	100 / 100	25 ms	6868 KiB

ho_t2

//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <class T>
using Tree =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
#define int long long
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define rep(i, a, b) for (int i = a; i <= b; ++i)
#define per(i, b, a) for (int i = b; i >= a; --i)
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()
#define lsb(x) (x)&(-x)
#define bug(x) cerr << #x << " " << x << endl;
 
void setIO(string name = "") {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    if (!name.empty()) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
 
ll fexp(ll a, ll b, ll m) {
    if (b == 0) return 1LL;
    ll p = a;
    ll ans = 1;
    while (b > 0) {
        if (b % 2 != 0) ans = (ans * p) % m;
        p = (p * p) % m;
        b >>= 1;
    }
    return ans;
}
 
const int MAXN = 2e5 + 10;
const int INF = 1e18 + 5;
const int MOD = 1e9+7;
int a[MAXN], pfx[MAXN][3],n,k;

int hihi(int i, int j) {
    int lo = i+1, hi = n, ans = n+1;
    while (lo <= hi) {
        int mid = (lo+hi)/2;

        if (pfx[mid][j] - pfx[i][j] >= k) {
            ans = mid;
            hi = mid - 1;
        } else {
            lo = mid + 1;
        }
    }

    return ans;
}

void solve() {
    string s;
    cin >> n >> k >> s;
    rep(i,1,n) {
        if (s[i-1]=='J') a[i] = 0;
        else if (s[i-1] == 'O') a[i] = 1;
        else a[i] = 2;

        pfx[i][a[i]]++;
        rep(j,0,2) pfx[i][j] += pfx[i-1][j];
    }

    int ans = INF;
    rep(l,1,n) {
        int sz = hihi(l-1,0);
        sz = hihi(sz,1);
        sz = hihi(sz,2);
        if (sz <= n) ans = min(ans, sz-l+1-3*k);
    }
    cout << (ans==INF?-1:ans) << '\n';
}

int32_t main() {
    setIO();
    int tt = 1;
    //cin >> tt;
 
    while (tt-- > 0) solve();
    return 0;
}

Compilation message (stderr)

ho_t2.cpp: In function 'void setIO(std::string)':
ho_t2.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t2.cpp:30:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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