Submission #1015379

#	Time	Username	Problem	Language	Result	Execution time	Memory
1015379		overwatch9	Watching (JOI13_watching)	C++17	100 / 100	285 ms	15424 KiB

watching

#include <bits/stdc++.h>
using namespace std;
int n;
vector <int> events;
vector <vector <int>> dp;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int p, q;
    cin >> n >> p >> q;
    events = vector <int> (n+1);
    for (int i = 1; i <= n; i++)
        cin >> events[i];
    sort(events.begin(), events.end());
    if (p + q >= n) {
        cout << 1 << '\n';
        return 0;
    }
    dp = vector <vector <int>> (n+1, vector <int> (p+1, 1e9));
    int lo = 1, hi = 1e9/2;
    while (lo < hi) {
        int mid = lo + (hi - lo) / 2;
        dp[0][0] = 0;
        vector <int> prev(n+1), prev2(n+1);
        int pt = 0, pt2 = 0;
        for (int i = 1; i <= n; i++) {
            while (events[i] - mid >= events[pt])
                pt++;
            prev[i] = pt;
            while (events[i] - mid*2 >= events[pt2])
                pt2++;
            prev2[i] = pt2;
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j <= p; j++) {
                dp[i][j] = 1e9;
                if (j-1 >= 0)
                    dp[i][j] = dp[i][j-1];
                int it = prev2[i];
                dp[i][j] = min(dp[i][j], dp[max(0, it-1)][j] + 1); 
                if (j > 0) {
                    it = prev[i];
                    dp[i][j] = min(dp[i][j], dp[max(0, it-1)][j-1]);
                }
            }
        }
        if (dp[n][p] > q)
            lo = mid + 1;
        else
            hi = mid;
    }
    cout << lo << '\n';
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50