oj.uz

Submission #863942

# Submission time Handle Problem Language Result Execution time Memory
863942 2023-10-21T13:52:35 Z prohacker Watching (JOI13_watching) C++14
100 / 100
 204 ms 16216 KB 
#include <bits/stdc++.h>
#define ll long long
#define ld long double

using namespace std;

const int N = 2010;
const int INF = INT_MAX;
const int mod = 1e9+7;

int n,p,q,a[N];
int dp[N][N];

bool check(int mid) {
    for(int i = 1 ; i <= n ; i++) {
        for(int j = 0 ; j <= q ; j++) {
            dp[i][j] = mod;
        }
    }
    for(int i = 1, j = 1, k = 1 ; i <= n ; i++) {
        while(j < i && a[i]-a[j] >= mid) {
            j++;
        }
        while(k < i && a[i]-a[k] >= mid*2) {
            k++;
        }
        for(int l = 0 ; l <= q ; l++) {
            dp[i][l] = dp[j-1][l]+1;
        }
        for(int l = 0 ; l <= q ; l++) {
            dp[i][l+1] = min(dp[i][l+1],dp[k-1][l]);
        }
    }
    for(int i = 0 ; i <= q  ; i++) {
        if(dp[n][i] <= p) {
            return true;
        }
    }
    return false;
}

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

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:64:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   64 |         int mid = l + r >> 1;
      |                   ~~^~~
watching.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen("WATCHING.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:46:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |         freopen("WATCHING.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:73:13: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   73 |     cout << ans;
      |             ^~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2392 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 1 ms 2396 KB Output is correct
13 Correct 1 ms 2428 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 15452 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 476 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 4 ms 15452 KB Output is correct
8 Correct 80 ms 15964 KB Output is correct
9 Correct 16 ms 15452 KB Output is correct
10 Correct 14 ms 15616 KB Output is correct
11 Correct 204 ms 16216 KB Output is correct
12 Correct 113 ms 16192 KB Output is correct
13 Correct 5 ms 15448 KB Output is correct
14 Correct 4 ms 15448 KB Output is correct
15 Correct 5 ms 15452 KB Output is correct