oj.uz

Submission #153007

# Submission time Handle Problem Language Result Execution time Memory
153007 2019-09-11T09:47:30 Z georgerapeanu Watching (JOI13_watching) C++11
100 / 100
 187 ms 16060 KB 
#include <cstdio>
#include <algorithm>

using namespace std;

int n,p,q;
int a[2005];
int dp[2005][2005];

bool ok(int w){
    if(n <= p + q){
        return true;
    }

    int l1 = 0;
    int l2 = 0;

    for(int i = 1;i <= n;i++){
        while(l1 < i && a[i] - a[l1 + 1] >= w){
            l1++;
        }
        while(l1 < i && a[i] - a[l2 + 1] >= 2 * w){
            l2++;
        }
        for(int j = 0;j <= p;j++){
            dp[i][j] = dp[l2][j] + 1;
            if(j){
                dp[i][j] = min(dp[i][j],dp[l1][j - 1]);
            }          
        }
    }

    for(int i = 0;i <= p;i++){
        if(dp[n][i] <= q){
            return true;
        }
    }

    return false;
}

int main(){

    scanf("%d %d %d",&n,&p,&q);

    for(int i = 1;i <= n;i++){
        scanf("%d",&a[i]);
    }

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

    int st = 0;
    int dr = 1e9;

    while(dr - st > 1){
        int mid = st + (dr - st) / 2;
        
        if(ok(mid)) {
            dr = mid;
        }
        
        else {
            st = mid;
        }
    }

    printf("%d\n",dr);

    return 0;
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d",&n,&p,&q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~
watching.cpp:47:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
         ~~~~~^~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 888 KB Output is correct
2 Correct 2 ms 256 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 760 KB Output is correct
8 Correct 3 ms 760 KB Output is correct
9 Correct 3 ms 632 KB Output is correct
10 Correct 2 ms 760 KB Output is correct
11 Correct 3 ms 760 KB Output is correct
12 Correct 3 ms 760 KB Output is correct
13 Correct 3 ms 760 KB Output is correct
14 Correct 2 ms 760 KB Output is correct
15 Correct 2 ms 760 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8312 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 3 ms 376 KB Output is correct
5 Correct 3 ms 376 KB Output is correct
6 Correct 3 ms 376 KB Output is correct
7 Correct 12 ms 8444 KB Output is correct
8 Correct 25 ms 9336 KB Output is correct
9 Correct 85 ms 14316 KB Output is correct
10 Correct 187 ms 16060 KB Output is correct
11 Correct 19 ms 9080 KB Output is correct
12 Correct 105 ms 15992 KB Output is correct
13 Correct 11 ms 8440 KB Output is correct
14 Correct 17 ms 8568 KB Output is correct
15 Correct 13 ms 8440 KB Output is correct