Submission #1176194

#	Time	Username	Problem	Language	Result	Execution time	Memory
1176194		vnedu	Watching (JOI13_watching)	C++17	100 / 100	156 ms	16668 KiB

watching

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

template<class T> bool maximize(T &a, const T &b){ return (a < b ? a = b, 1 : 0); }
template<class T> bool minimize(T &a, const T &b){ return (a > b ? a = b, 1 : 0); }

#define fi first
#define se second

#define pb push_back
#define ii pair<int, int>

#define all(x) x.begin(), x.end()

#define TASK "nonsense"

/// end of template ///

const int N = 2e3 + 23;
int n,p,q,a[N];
namespace sub1
{
    bool check()
    {
        return (n<=100);
    }
    const int N = 102;
    bool dp[N][N][N];
    bool check(int w)
    {
        memset(dp,0,sizeof(dp));
        for (int j=0; j<N; ++j) for (int k=0; k<N; ++k) dp[0][j][k]=1;
        for (int i=1; i<=n; ++i)
        {
            int cmp,cmq;
            for (int j=i; j>=1; --j)
            {
                if (a[i]-a[j]+1<=w) cmp=j;
                if (a[i]-a[j]+1<=2*w) cmq=j;
            }
            for (int j=0; j<=n; ++j) for (int k=0; k<=n; ++k)
            {
                bool &cur=dp[i][j][k];
                if (j)
                {
                    cur|=dp[cmp-1][j-1][k];
                }
                if (k)
                {
                    cur|=dp[cmq-1][j][k-1];
                }
            }
        }
        return dp[n][min(n,p)][min(n,q)];
    }
    void solve()
    {
        int lo=1,hi=1e9,mid,ans;
        while (lo<=hi)
        {
            mid=(lo+hi)>>1;
            if (check(mid)) ans=mid,hi=mid-1;
            else lo=mid+1;
        }
        cout<<ans;
    }
}
namespace subfull
{
    int dp[N][N];
    bool check(int w)
    {
        memset(dp,0,sizeof(dp));
        for (int i=1; i<=n; ++i)
        {
            int cmp,cmq;
            for (int j=i; j>=1; --j)
            {
                if (a[i]-a[j]+1<=w) cmp=j;
                if (a[i]-a[j]+1<=2*w) cmq=j;
            }
            for (int j=0; j<=n; ++j)
            {
                int &cur=dp[i][j]; cur=INT_MAX;
                if (j>0) minimize(cur,dp[cmp-1][j-1]);
                minimize(cur,dp[cmq-1][j]+1);
            }
        }
        return (dp[n][min(n,p)]<=q);
    }
    void solve()
    {
        int lo=1,hi=1e9,mid,ans;
        while (lo<=hi)
        {
            mid=(lo+hi)>>1;
            if (check(mid)) ans=mid,hi=mid-1;
            else lo=mid+1;
        }
        cout<<ans;
    }
}
void solve()
{
    cin>>n>>p>>q;
    for (int i=1; i<=n; ++i) cin>>a[i];
    sort(a+1,a+1+n);
    if (sub1::check()) return void(sub1::solve());
    return void(subfull::solve());
}

int main()  {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

//    freopen(TASK".inp","r",stdin);
//    freopen(TASK".out","w",stdout);

    int testcase=1;
//    cin>>testcase;

    while (testcase--)
        solve();

//    #define TIME  (1.0 * clock() / CLOCKS_PER_SEC)
//    cerr << "Time elapsed: " << TIME << " s.\n";
    return 0;
}

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