Submission #309861

#	Time	Username	Problem	Language	Result	Execution time	Memory
309861		Kripton	Watching (JOI13_watching)	C++14	100 / 100	392 ms	27064 KiB

watching

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
int n,p,q;
vector <int> vec[2001];
int v[2001];
int dp[2001][2001];// dp[i][j]=nr minim de garduri MARI ca sa acopere primele i puncte, folosind si j garduri MICI
int where_to(int start,int mar)
{
    int r=start,pas=1<<10;
    while(pas)
    {
        if(r+pas<=n&&v[r+pas]-v[start]+1<=mar)
            r+=pas;
        pas/=2;
    }
    return r;
}
bool verif(int w)
{
    int i,j;
    for(i=1; i<=n; i++)
        vec[i].clear();
    for(i=1; i<=n; i++)
        for(j=0; j<=n; j++)
            dp[i][j]=INT_MAX;
    int x=where_to(1,w),y=where_to(1,2*w);
    vec[x].push_back(1);
    dp[x][1]=0;
    vec[y].push_back(0);
    dp[y][0]=1;
    for(i=1; i<n; i++)
    {
        x=where_to(i+1,w);
        y=where_to(i+1,2*w);
        for(j=0; j<vec[i].size(); j++)
        {
            if(x!=i&&vec[i][j]+1<=p&&dp[i][vec[i][j]]<dp[x][vec[i][j]+1])
            {
                if(dp[x][vec[i][j]+1]==INT_MAX)
                    vec[x].push_back(vec[i][j]+1);
                dp[x][vec[i][j]+1]=dp[i][vec[i][j]];
            }
            if(y!=i&&dp[i][vec[i][j]]+1<dp[y][vec[i][j]])
            {
                if(dp[y][vec[i][j]]==INT_MAX)
                    vec[y].push_back(vec[i][j]);
                dp[y][vec[i][j]]=dp[i][vec[i][j]]+1;
            }
        }
    }
    for(i=0;i<vec[n].size();i++)
        if(dp[n][vec[n][i]]<=q)
            break;
    if(i==vec[n].size())
        return 0;
    return 1;
}
int cautbin()
{
    int r=0,pas=1<<30;
    while(pas)
    {
        if(!verif(r+pas))
            r+=pas;
        pas/=2;
    }
    return r+1;
}
int main()
{
#ifdef HOME
    freopen("test.in","r",stdin);
    freopen("test.out","w",stdout);
#endif // HOME
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>n>>p>>q;
    if(p+q>=n)
    {
        cout<<1;
        return 0;
    }
    for(int i=1; i<=n; i++)
        cin>>v[i];
    sort(v+1,v+n+1);
    cout<<cautbin();
    return 0;
}

Compilation message (stderr)

watching.cpp: In function 'bool verif(int)':
watching.cpp:36:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         for(j=0; j<vec[i].size(); j++)
      |                  ~^~~~~~~~~~~~~~
watching.cpp:52:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |     for(i=0;i<vec[n].size();i++)
      |             ~^~~~~~~~~~~~~~
watching.cpp:55:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |     if(i==vec[n].size())
      |        ~^~~~~~~~~~~~~~~

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