oj.uz

Submission #147281

# Submission time Handle Problem Language Result Execution time Memory
147281 2019-08-28T17:42:44 Z karma Watching (JOI13_watching) C++11
100 / 100
 635 ms 30328 KB 
#include<bits/stdc++.h>
#pragma GCC optimization ("O3")
#define ll  long long

using namespace std;

const int N = 2007;

ll n, pos[N], p, q, f[N][N];

bool Check(ll w)
{
     int k = 1, l;
     f[0][0] = 0;
     for(int j = 1; j <= n; ++j) {
        while(pos[j] - pos[k] >= 2 * w) ++k;
        f[0][j] = f[0][k - 1] + 1;
     }
     for(int i = 1; i <= p; ++i) {
        k = l = 1; f[i][0] = 0;
        for(int j = 1; j <= n; ++j) {
           while(pos[j] - pos[k] >= 2 * w) ++k;
           while(pos[j] - pos[l] >= w) ++l;
           f[i][j] = min({f[i][k - 1] + 1, f[i - 1][j], f[i - 1][l - 1]});
        }
     }
     return f[p][n] <= q;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    if(fopen("test.inp", "r")) {
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    cin >> n >> p >> q;
    for(int i = 1; i <= n; ++i) cin >> pos[i];
    if(p + q >= n) return cout << 1, 0;
    sort(pos + 1, pos + n + 1);
    ll l = 1, h = (ll)1e9;
    while(l <= h) {
       ll mid = (l + h) >> 1;
       if(Check(mid)) h = mid - 1;
       else l = mid + 1;
    }
    cout << l;
}

Compilation message

watching.cpp:2:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
watching.cpp: In function 'int main()':
watching.cpp:35:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen("test.inp", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen("test.out", "w", stdout);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 3 ms 632 KB Output is correct
12 Correct 3 ms 632 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 2 ms 376 KB Output is correct
15 Correct 2 ms 376 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 8 ms 632 KB Output is correct
8 Correct 46 ms 2296 KB Output is correct
9 Correct 261 ms 12244 KB Output is correct
10 Correct 635 ms 30328 KB Output is correct
11 Correct 34 ms 1788 KB Output is correct
12 Correct 332 ms 15836 KB Output is correct
13 Correct 6 ms 632 KB Output is correct
14 Correct 8 ms 632 KB Output is correct
15 Correct 7 ms 632 KB Output is correct