Submission #396737

#	Time	Username	Problem	Language	Result	Execution time	Memory
396737		danielcm585	Martian DNA (BOI18_dna)	C++14	100 / 100	63 ms	2460 KiB

dna

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second

typedef long long ll;
typedef pair<int,int> ii;

const int N = 2e5;
int n, k, r;
int a[N+2], cnt[N+2], need[N+2];

bool can(int mid) {
    memset(cnt,0,sizeof(cnt));
    int get = 0;
    for (int i = 1; i <= n; i++) {
        cnt[a[i]]++;
        get += (need[a[i]] && cnt[a[i]] == need[a[i]]);
        if (i-mid >= 1) {
            get -= (need[a[i-mid]] && cnt[a[i-mid]] == need[a[i-mid]]);
            cnt[a[i-mid]]--;
        }
        if (i >= mid && get == r) return 1;
    }
    return 0;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> k >> r;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= r; i++) {
        int b, q; cin >> b >> q;
        need[b] = q;
    }
    int ans = -1;
    for (int l = 1, r = n; l <= r; ) {
        int mid = (l+r)/2;
        if (can(mid)) {
            ans = mid;
            r = mid-1;
        }
        else l = mid+1;
    }
    if (ans == -1) cout << "impossible\n";
    else cout << ans << '\n';
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 24 / 24
• Subtask 3: 28 / 28
• Subtask 4: 32 / 32