oj.uz

Submission #21055

# Submission time Handle Problem Language Result Execution time Memory
21055 2017-04-04T05:52:57 Z sbansalcs Watching (JOI13_watching) C++14
100 / 100
 396 ms 17724 KB 
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
const int N = 2003;
ll arr[N];
int A[N],B[N];
int dp[N][N];
int n,p,q;

int bs(int f,ll a)   {
    int lx=f+1,rx=n+1,mx;
    while (lx<rx) {
        mx=(lx+rx)/2;
        if(arr[mx]>=a)  rx=mx;
        else    lx=mx+1;
    }
    return lx;
}

bool check(ll w)   {
    for (int i=1; i<=n; i++) {
        A[i]=bs(i,arr[i]+w);
        B[i]=bs(i,arr[i]+2*w);
    }
    for (int i=n+1; i>=1; i--) {
        for (int j=0; j<=q; j++) {
            if(i==n+1)  dp[i][j]=0;
            else    {
                dp[i][j]=1+dp[A[i]][j];
                if(j!=0)    {
                    dp[i][j]=min(dp[i][j],dp[B[i]][j-1]);
                    dp[i][j]=min(dp[i][j],dp[i][j-1]);
                }
            }
        }
    }
    return dp[1][q]<=p;
}

int main() {
    scanf("%d %d %d",&n,&p,&q);
    for (int i=1; i<=n; i++) {
        scanf("%lld",arr+i);
    }
    if(p+q>=n)  {
        cout<<1<<endl;return 0;
    }
    sort(arr+1,arr+1+n);
    arr[n+1]=2e9;
    int lx=1,rx=1e9,mx;
    while (lx<rx) {
        mx=(lx+rx)/2;
        if(check(mx))   rx=mx;
        else    lx=mx+1;
    }
    cout<<lx<<endl;
    return 0;
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:42:31: 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:44:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld",arr+i);
                            ^

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17724 KB Output is correct
2 Correct 0 ms 17724 KB Output is correct
3 Correct 0 ms 17724 KB Output is correct
4 Correct 0 ms 17724 KB Output is correct
5 Correct 0 ms 17724 KB Output is correct
6 Correct 0 ms 17724 KB Output is correct
7 Correct 0 ms 17724 KB Output is correct
8 Correct 0 ms 17724 KB Output is correct
9 Correct 0 ms 17724 KB Output is correct
10 Correct 0 ms 17724 KB Output is correct
11 Correct 0 ms 17724 KB Output is correct
12 Correct 0 ms 17724 KB Output is correct
13 Correct 0 ms 17724 KB Output is correct
14 Correct 0 ms 17724 KB Output is correct
15 Correct 0 ms 17724 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 17724 KB Output is correct
2 Correct 0 ms 17724 KB Output is correct
3 Correct 0 ms 17724 KB Output is correct
4 Correct 0 ms 17724 KB Output is correct
5 Correct 0 ms 17724 KB Output is correct
6 Correct 0 ms 17724 KB Output is correct
7 Correct 9 ms 17724 KB Output is correct
8 Correct 163 ms 17724 KB Output is correct
9 Correct 36 ms 17724 KB Output is correct
10 Correct 29 ms 17724 KB Output is correct
11 Correct 396 ms 17724 KB Output is correct
12 Correct 209 ms 17724 KB Output is correct
13 Correct 9 ms 17724 KB Output is correct
14 Correct 9 ms 17724 KB Output is correct
15 Correct 9 ms 17724 KB Output is correct