Submission #25426

#	Time	Username	Problem	Language	Result	Execution time	Memory
25426		tlwpdus	Watching (JOI13_watching)	C++98	100 / 100	283 ms	19268 KiB

watching

#include <bits/stdc++.h>

using namespace std;

int dyn[2100][2100];
int prev[2][2100];
int n, p, q;
int arr[2100];

bool ok(int w) {
    int i, j;
    for (i=1;i<=n;i++) {
        prev[0][i] = upper_bound(arr,arr+i,arr[i]-w)-arr-1;
        prev[1][i] = upper_bound(arr,arr+i,arr[i]-w*2)-arr-1;
    }
    for (i=1;i<=n;i++) {
        for (j=0;j<=n;j++) {
            dyn[i][j] = min(((j)?dyn[prev[1][i]][j-1]:987654321),dyn[prev[0][i]][j]+1);
        }
    }
    return dyn[n][min(q,n)]<=p;
}

int main() {
    int i;
    scanf("%d%d%d",&n,&p,&q);
    arr[0] = -(1e9+10);
    for (i=1;i<=n;i++) scanf("%d",&arr[i]);
    sort(arr,arr+n+1);
    int s = 1, e = 5e8+3;
    while(s<=e) {
        int m = (s+e)>>1;
        if (ok(m)) e = m-1;
        else s = m+1;
    }
    printf("%d\n",s);
    return 0;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:26:29: 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:28:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (i=1;i<=n;i++) scanf("%d",&arr[i]);
                                           ^

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50