Submission #1143050

#	Time	Username	Problem	Language	Result	Execution time	Memory
1143050		Noproblem29	Monochrome Points (JOI20_monochrome)	C++20	35 / 100	2092 ms	14028 KiB

monochrome

#include<bits/stdc++.h>
using namespace std;
#ifndef BADGNU
#pragma GCC target("sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#endif
#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds;
#define ll long long
#define int ll
#define ld long double
#define y1 cheza
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> using ordered_set = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
template<class T> using ordered_multiset = tree<T,null_type,less_equal<T>,rb_tree_tag,tree_order_statistics_node_update>;
const int N=4e5+100;
const int M=5001;
const int B=447;
const int mod=998244353;
const ll INF=1e18;
const int dx[]={1,-1,0,0};
const int dy[]={0,0,1,-1};
const double eps=1e-6;
int n;
vector<int>f[2];
int d[N];
void upd(int r,int x){
    for(;r<=2*n;r+=(-r&r)){
        d[r]+=x;
    }
}
int calc(int r){
    int res=0;
    for(;r>0;r-=(-r&r)){
        res+=d[r];
    }
    return res;
}
void test(){
    cin>>n;
    for(int i=1;i<=n*2;i++){
        char x;
        cin>>x;
        if(x=='W'){
            f[0].push_back(i);
        }
        else{
            f[1].push_back(i);
        }
    }
    sort(f[0].begin(),f[0].end());
    sort(f[1].begin(),f[1].end());
    int ans=0;
    for(int k=0;k<=n;k++){
        vector<pair<int,int>>v;
        for(int j=1;j<=2*n;j++){
            d[j]=0;
        }
        for(int i=0;i<n;i++){
            v.push_back({f[0][i],f[1][(i+k)%n]});
            if(v.back().first>v.back().second){
                swap(v.back().first,v.back().second);
            }
        }
        sort(v.begin(),v.end());
        int res=0;
        for(auto [a,b]:v){
            res+=(calc(b)-calc(a));
            upd(b,1);
        }
        ans=max(ans,res);

    }
    cout<<ans<<'\n';
}



/*

*/
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    // cout.tie(nullptr);
    int t2=1;
    // cin>>t2;
    for(int i=1;i<=t2;i++){
        test();
    }
}

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