Submission #1126953

#	Time	Username	Problem	Language	Result	Execution time	Memory
1126953		_rain_	Ekoeko (COCI21_ekoeko)	C++20	30 / 110	6 ms	2072 KiB

Main

#include<bits/stdc++.h>
using namespace std;

typedef long long LL;
#define inp(data_name) freopen(data_name,"r",stdin);
#define out(data_name) freopen(data_name,"w",stdout);
#define name "main"
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define FORD(i,a,b) for(int i=(b);i>=(a);--i)

#define N 2'00'000
vector<int>pos[27],serve2;
int total[27]={},cnt[27]={},times=0;
string s;
int n;

int BIT[N+2]={};
void upd(int id,int val){
    for(;id<=n;id+=id&-id) BIT[id]+=val;
}
int Get(int id){
    int sum=0;
    for(;id;id-=id&-id) sum+=BIT[id];
    return sum;
}

int32_t main(){
    ios::sync_with_stdio(0); 
    cin.tie(0); cout.tie(0);
    cin>>n>>s; s='#'+s;
    FOR(i,1,2*n) total[s[i]-'a']++;
    LL ans=0;
    int cur=n;
    FOR(i,1,2*n){
        ++cnt[s[i]-'a'];
        if (cnt[s[i]-'a']>total[s[i]-'a']/2){
            ++cur;
            if (i<n+1) ans+=(cur-i);
            serve2.push_back({pos[s[i]-'a'][cnt[s[i]-'a']-total[s[i]-'a']/2-1]});
        }
        else {
            ++times;
            pos[s[i]-'a'].push_back(times);
        }
    }
    cur=0;
    for(auto&x:serve2) {
        ans+=Get(n)-Get(x);
        upd(x,1);
        ++cur;
    }
    printf("%lld",ans);
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 40