Submission #587772

#	Time	Username	Problem	Language	Result	Execution time	Memory
587772		MohamedFaresNebili	Watching (JOI13_watching)	C++14	100 / 100	383 ms	31820 KiB

watching

#include <bits/stdc++.h>
/// #pragma GCC optimize ("Ofast")
/// #pragma GCC target ("avx2")
/// #pragma GCC optimize("unroll-loops")

        using namespace std;

        using ll = long long;
        using ii = pair<ll, ll>;
        using vi = vector<int>;

        #define ff first
        #define ss second
        #define pb push_back
        #define all(x) (x).begin(), (x).end()
        #define lb lower_bound
        #define int ll

        const int MOD = 1000 * 1000 * 1000 + 7;

        int N, P, Q, A[2001], DP[2001][2001];
        int solve(int v) {
            int X[N], Y[N];
            for(int l = 0, i = 0; l < N; l++) {
                while(A[l] - A[i] >= v) i++;
                X[l] = i;
            }
            for(int l = 0, i = 0; l < N; l++) {
                while(A[l] - A[i] >= 2 * v) i++;
                Y[l] = i;
            }
            for(int l = 0; l <= N; l++)
                for(int i = 0; i <= P; i++)
                    DP[l][i] = 1e9 + 7;
            DP[0][0] = 0;
            for(int l = 1; l <= N; l++) {
                for(int i = 0; i <= P; i++) {
                    if(i > 0) DP[l][i] = min(DP[l][i], DP[X[l - 1]][i - 1]);
                    if(DP[Y[l - 1]][i - 1] != 1e9 + 7)
                        DP[l][i] = min(DP[l][i], DP[Y[l - 1]][i] + 1);
                }
            }
            for(int l = 0; l <= P; l++)
                if(DP[N][l] <= Q) return 1;
            return 0;
        }

		int32_t main() {
            ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
            cin >> N >> P >> Q;
            P = min(P, N), Q = min(Q, N);
            for(int l = 0; l < N; l++) cin >> A[l];
            sort(A, A + N);
            int lo = 1, hi = 1e9, res = 1e9 + 7;
            while(lo <= hi) {
                int md = (lo + hi) / 2;
                if(solve(md)) hi = md - 1, res = md;
                else lo = md + 1;
            }
            cout << res << "\n";
            return 0;
		}

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