Submission #516558

#	Time	Username	Problem	Language	Result	Execution time	Memory
516558		leinad2	Monochrome Points (JOI20_monochrome)	C++17	25 / 100	2070 ms	332 KiB

monochrome

#include<bits/stdc++.h>
using namespace std;
int n, i, j, k, a, b, ans;
char S[400010];
vector<int>A, B;
main()
{
    scanf("%d", &n);
    scanf("%s", &S);
    for(i=0;i<2*n;i++)
    {
        if(S[i]=='B')A.push_back(i+1);
        else B.push_back(i+1);
    }
    for(i=0;i<n;i++)
    {
        vector<pair<int, int> >V;
        for(j=i;j<n;j++)V.push_back({A[j-i], B[j]});
        for(j=0;j<i;j++)V.push_back({A[j+n-i], B[j]});
        for(auto &p:V)if(p.first>p.second)swap(p.first, p.second);
        int res=0;
        for(j=0;j<V.size();j++)for(k=j+1;k<V.size();k++)
        {
            if((V[j].first<V[k].first&&V[k].first<V[j].second&&V[j].second<V[k].second)||(V[k].first<V[j].first&&V[j].first<V[k].second&&V[k].second<V[j].second))res++;
        }
        ans=max(ans, res);
    }
    cout<<ans;
}

Compilation message (stderr)

monochrome.cpp:6:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    6 | main()
      | ^~~~
monochrome.cpp: In function 'int main()':
monochrome.cpp:9:13: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[400010]' [-Wformat=]
    9 |     scanf("%s", &S);
      |            ~^   ~~
      |             |   |
      |             |   char (*)[400010]
      |             char*
monochrome.cpp:22:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |         for(j=0;j<V.size();j++)for(k=j+1;k<V.size();k++)
      |                 ~^~~~~~~~~
monochrome.cpp:22:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |         for(j=0;j<V.size();j++)for(k=j+1;k<V.size();k++)
      |                                          ~^~~~~~~~~
monochrome.cpp:8:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
monochrome.cpp:9:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     scanf("%s", &S);
      |     ~~~~~^~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 0 / 10
• Subtask 4: 0 / 65