Submission #572603

#	Time	Username	Problem	Language	Result	Execution time	Memory
572603		groshi	Monochrome Points (JOI20_monochrome)	C++17	100 / 100	52 ms	5764 KiB

monochrome

#include<iostream>
#include<vector>
#include<string>
using namespace std;
#define int long long
vector<int> b,w;
int n;
int wyn(int ile)
{
    int wynik=0;
    for(int i=0;i<b.size();i++)
    {
        int l=b[i];
        int r=w[(i+ile)%n];
        if(l>r)
            swap(l,r);
        int ile1=(r-l-1);
        int ile2=2*n-ile1-2;
        wynik+=min(ile1,ile2);
    }
    return wynik/2;
}
int32_t main()
{
    cin.tie(0);
    cout.tie(0);
    ios_base::sync_with_stdio(0);
    cin>>n;
    string s;
    cin>>s;
    for(int i=0;i<s.length();i++)
        if(s[i]=='B')
            b.push_back(i);
        else w.push_back(i);
    int pocz=0,kon=n,sre,ostd=0;
    while(pocz<kon)
    {
        sre=(pocz+kon)/2;
        if(wyn(sre)<wyn(sre+1))
        {
            ostd=sre+1;
            pocz=sre+1;
        }
        else kon=sre;
    }
    //for(int i=0;i<n;i++)
        //cout<<wyn(i)<<" ";
    cout<<wyn(ostd);
    return 0;
}

Compilation message (stderr)

monochrome.cpp: In function 'long long int wyn(long long int)':
monochrome.cpp:11:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |     for(int i=0;i<b.size();i++)
      |                 ~^~~~~~~~~
monochrome.cpp: In function 'int32_t main()':
monochrome.cpp:31:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for(int i=0;i<s.length();i++)
      |                 ~^~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 10 / 10
• Subtask 4: 65 / 65