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Submission #228360

# Submission time Handle Problem Language Result Execution time Memory
228360 2020-04-30T18:47:55 Z Nayna Watching (JOI13_watching) C++14
50 / 100
 1000 ms 31744 KB 
#include <bits/stdc++.h>

using namespace std;
const int mxn = 2e3+5;
typedef long long ll;
const ll inf = 1e16;
ll arr[mxn];
ll dp[mxn][mxn];
ll n, P, Q;

bool solve(ll w)
{
    for(int i = 0; i <= n; i++)
        for(int r = 0; r <= n; r++) dp[i][r] = inf;
    dp[0][0] = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int r = 0; r <= P; r++)
        {
            int x = upper_bound(arr+1, arr+n+1, arr[i]-w)-arr-1;
            int y = upper_bound(arr+1, arr+n+1, arr[i]-w-w)-arr-1;
            if(r) dp[i][r] = min(dp[i][r], dp[x][r-1]);
            dp[i][r] = min(dp[i][r], dp[y][r]+1);
        }
    }
    for(int i = 0; i <= n; i++)
        if(dp[n][i]<=Q) return true;
    return false;
}
int main()
{

    scanf("%lld%lld%lld", &n, &P, &Q);

    P = min(n, P);
    Q = min(n, Q);

    for(int i = 1; i <= n; i++) scanf("%lld", &arr[i]);

    sort(arr+1, arr+n+1);

    ll lo = 1, hi = 1e9+5, ans = inf;

    while(lo<=hi)
    {
        ll mid = (lo+hi)>>1;
        if(solve(mid))
        {
            hi = mid-1;
            ans = min(ans, mid);
        }
        else lo = mid+1;
    }
    printf("%lld\n", ans);
    return 0;
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:33:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld%lld%lld", &n, &P, &Q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:38:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1; i <= n; i++) scanf("%lld", &arr[i]);
                                 ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 768 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 4 ms 384 KB Output is correct
4 Correct 11 ms 896 KB Output is correct
5 Correct 5 ms 768 KB Output is correct
6 Correct 11 ms 768 KB Output is correct
7 Correct 5 ms 896 KB Output is correct
8 Correct 5 ms 768 KB Output is correct
9 Correct 6 ms 768 KB Output is correct
10 Correct 6 ms 768 KB Output is correct
11 Correct 9 ms 768 KB Output is correct
12 Correct 8 ms 768 KB Output is correct
13 Correct 5 ms 768 KB Output is correct
14 Correct 6 ms 768 KB Output is correct
15 Correct 5 ms 768 KB Output is correct

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 140 ms 31744 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Execution timed out 1085 ms 31744 KB Time limit exceeded
4 Halted 0 ms 0 KB -