oj.uz

Submission #285282

# Submission time Handle Problem Language Result Execution time Memory
285282 2020-08-28T15:29:25 Z leductoan Watching (JOI13_watching) C++14
100 / 100
 358 ms 8696 KB 
#include<bits/stdc++.h>
using namespace std;
#define task "watching"
#define lb lower_bound
#define ub upper_bound
#define ALL(v) (v).begin(),(v).end()
#define zs(v) int((v).size())
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define FOR(i,a,b) for(int i=(a),_b=(b);i<=_b;++i)
#define FORD(i,b,a) for(int i=(b),_a=(a);i>=_a;--i)
#define FOR_(i,a,b) for(int i=(a),_b=(b);i<_b;++i)
typedef long double ld;
typedef long long ll;
typedef pair<int,int> pii;
const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};
const ll mod=1000000007; /// 998244353
const int base=311;
const int N=2e3+5;

int n,s,l,dp[N][N];
ll a[N];

int check(int val)
{
    for(int i=0;i<=s;++i)
    {
        for(int j=0;j<=l;++j)
        {
            dp[i][j]=-1;
        }
    }
    dp[0][0]=0;
    for(int i=0;i<=s;++i)
    {
        for(int j=0;j<=l;++j)
        {
            if(dp[i][j]==-1) continue;
            if(dp[i][j]==n) return true;
            int l=dp[i][j]+1, r=n;
            int id=-1;
            while(l<=r)
            {
                int mid=(l+r)>>1;
                if(a[mid]-a[dp[i][j]+1]+1<=val) id=mid, l=mid+1;
                else r=mid-1;
            }
            dp[i+1][j]=max(dp[i+1][j],id);

            l=dp[i][j]+1, r=n;
            id=-1;
            while(l<=r)
            {
                int mid=(l+r)>>1;
                if(a[mid]-a[dp[i][j]+1]+1<=2*val) id=mid, l=mid+1;
                else r=mid-1;
            }
            dp[i][j+1]=max(dp[i][j+1],id);
        }
    }

    return dp[s][l]>=n;
}
void biot()
{
    cin>>n>>s>>l;
    if(s+l>=n)
    {
        cout<<1;
        return;
    }
    for(int i=1;i<=n;++i) cin>>a[i];
    sort(a+1,a+n+1);
    int l=1, r=1e9, ans=0;
//    cout<<check(16)<<endl;
    while(l<=r)
    {
        int mid=(l+r)>>1;
        if(check(mid)) ans=mid,r=mid-1;
        else l=mid+1;
    }
    cout<<ans;
}
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    if(fopen(task".inp","r"))
    {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    biot();
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   92 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
watching.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   93 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 0 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 640 KB Output is correct
12 Correct 1 ms 512 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 0 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 66 ms 1280 KB Output is correct
9 Correct 76 ms 3808 KB Output is correct
10 Correct 96 ms 8696 KB Output is correct
11 Correct 32 ms 1152 KB Output is correct
12 Correct 358 ms 8096 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct