Submission #145180

#	Time	Username	Problem	Language	Result	Execution time	Memory
145180		solimm4sks	Watching (JOI13_watching)	C++14	50 / 100	448 ms	31964 KiB

watching

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

long long n, p, q;
long long a[200005];
long long dp[2005][2005];

long long smallReach[2005];
long long bigReach[2005];

#define INF 10000

bool check(long long w){
    for(long long i = 0; i < n; ++i){
        for(long long j = 0; j <= p; ++j){
            dp[i][j] = INF;
        }
    }

    for(long long i = 0; i < n; ++i){
        long long ind1 = lower_bound(a, a + n, a[i] - w + 1) - a;
        long long ind2 = lower_bound(a, a + n, a[i] - 2 * w + 1) - a;

        smallReach[i] = ind1;
        bigReach[i] = ind2;
    }

    for(long long i = 1; i <= p; ++i){
        dp[0][i] = 0;
    }
    dp[0][0] = 1;

    for(long long i = 1; i < n; ++i){
        for(long long j = 0; j <= p; ++j){
            if(j){
                if(bigReach[i] == 0){
                    dp[i][j] = 1;
                }
                if(smallReach[i] == 0){
                    dp[i][j] = 0;
                }
                if(smallReach[i] && bigReach[i]){
                    dp[i][j] = min(dp[bigReach[i] - 1][j] + 1, dp[smallReach[i] - 1][j - 1]);
                }
            }else{
                if(bigReach[i] == 0){
                    dp[i][0] = 1;
                }else{
                    dp[i][0] = dp[bigReach[i] - 1][0] + 1;
                }
            }
        }
    }

    if(dp[n - 1][p] <= q){
        return true;
    }
    return false;
}


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> n >> p >> q;
    for(long long i = 0; i < n; ++i){
        cin >> a[i];
    }

    sort(a, a + n);

    p = min(p, n);
    q = min(q, n);

    long long l = 0;
    long long r = 1000000000;
    long long lc = -1;
    while(l <= r){
        long long mid = (l + r) / 2;
        bool ch = check(mid);
        if(ch){
            r = mid - 1;
            lc = mid;
        }else{
            l = mid + 1;
        }
    }

    cout << lc << "\n";
    return 0;
}

• Subtask 1: 0 / 50
• Subtask 2: 50 / 50