Submission #683896

#	Time	Username	Problem	Language	Result	Execution time	Memory
683896		alvingogo	Monochrome Points (JOI20_monochrome)	C++14	35 / 100	2069 ms	2656 KiB

monochrome

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define AquA cin.tie(0);ios_base::sync_with_stdio(0);
#define fs first
#define sc second
#define p_q priority_queue
#define int long long
using namespace std;

signed main(){
    AquA;
    int n;
    cin >> n;
    string s;
    cin >> s;
    int ans=1e14;
    vector<int> a,b;
    int pre=0,mx=0,k=0;
    for(int i=0;i<n;i++){
        if(s[i]=='B'){
            a.push_back(i);
            pre++;
        }
        if(s[i+n]=='W'){
            b.push_back(i);
            pre--;
        }
        if(pre<mx){
            mx=pre;
            k=i+1;
        }
    }
    int g=a.size();
    for(int i=0;i<g;i++){
        int xx=0;
        for(int j=0;j<g;j++){
            xx+=min(abs(b[j]-a[(i+j)%g]),n-abs(b[j]-a[(i+j)%g]));
        }
        ans=min(ans,xx);
    }
    if(g==0){
        ans=0;
    }
    cout << n*(n-1)/2-ans << "\n";
    return 0;
}

Compilation message (stderr)

monochrome.cpp: In function 'int main()':
monochrome.cpp:18:20: warning: variable 'k' set but not used [-Wunused-but-set-variable]
   18 |     int pre=0,mx=0,k=0;
      |                    ^

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