oj.uz

Submission #1052861

# Submission time Handle Problem Language Result Execution time Memory
1052861 2024-08-11T04:59:32 Z manhlinh1501 Watching (JOI13_watching) C++17
100 / 100
 78 ms 16228 KB 
#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
const int MAXN = 2e3 + 5;
const int oo32 = 1e9;

int N, P, Q;
int a[MAXN];
int dp[MAXN][MAXN];

bool check(int K) {
    memset(dp, 0x3f, sizeof dp);
    dp[0][0] = 0;
    int x = 0, y = 0;
    for(int i = 1; i <= N; i++) {
        while(x < i and a[x + 1] < a[i] - K + 1)
            x++;
        while(y < i and a[y + 1] < a[i] - 2 * K + 1)
            y++;
        for(int j = 0; j <= P; j++) {
            dp[i][j] = dp[y][j] + 1;
            if(j > 0) dp[i][j] = min(dp[i][j], dp[x][j - 1]);
        }
    }
    for(int i = 1; i <= P; i++) {
        if(dp[N][i] <= Q)
            return true;
    }
    return false;
}

signed main() {
#define TASK "code"

    if (fopen(TASK ".inp", "r")) {
        freopen(TASK ".inp", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> N >> P >> Q;
    for(int i = 1; i <= N; i++) cin >> a[i];
    if(P + Q >= N) return cout << 1, 0;
    P = min(P, N);
    Q = min(Q, N);
    sort(a + 1, a + N + 1);
    int low = 1, high = oo32;
    int ans = -1;
    while(low <= high) {
        int mid = (low + high) / 2;
        if(check(mid)) {
            ans = mid;
            high = mid - 1;
        } else low = mid + 1;
    }
    cout << ans;
    return (0 ^ 0);
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(TASK ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(TASK ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 15964 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 10 ms 16188 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 10 ms 16004 KB Output is correct
8 Correct 10 ms 16196 KB Output is correct
9 Correct 10 ms 15964 KB Output is correct
10 Correct 10 ms 15964 KB Output is correct
11 Correct 9 ms 16196 KB Output is correct
12 Correct 10 ms 16188 KB Output is correct
13 Correct 11 ms 16188 KB Output is correct
14 Correct 9 ms 15964 KB Output is correct
15 Correct 9 ms 16196 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 15964 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 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 11 ms 16216 KB Output is correct
8 Correct 15 ms 15964 KB Output is correct
9 Correct 38 ms 16220 KB Output is correct
10 Correct 78 ms 16196 KB Output is correct
11 Correct 13 ms 16220 KB Output is correct
12 Correct 44 ms 15964 KB Output is correct
13 Correct 11 ms 16216 KB Output is correct
14 Correct 11 ms 16228 KB Output is correct
15 Correct 12 ms 15964 KB Output is correct