Submission #1163575

#	Time	Username	Problem	Language	Result	Execution time	Memory
1163575		dzuizz	Ekoeko (COCI21_ekoeko)	C++20	0 / 110	3 ms	2488 KiB

Main

#include<bits/stdc++.h>
using namespace std;
//#define DEBUG
#define int long long
const int maxn=2e5+5;
int ft[maxn],n;
void add(int idx,int v){
	for(++idx;idx<=2*n;idx+=idx&-idx)
		ft[idx]+=v;
}
int sum(int idx){
	int ret=0;
	for(++idx;idx>0;idx-=idx&-idx)
		ret+=ft[idx];
	return ret;
}
int sum(int l,int r){
	return sum(r)-sum(l-1);
}
signed main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin>>n;
	string s; cin>>s;
	
	vector<int> v[26];
	for(int i=0;i<(int)s.size();++i){
		v[s[i]-'a'].emplace_back(i);
	}
	
	#ifdef DEBUG
	for(auto&x:v) {for(auto&e:x) cout<<e<<" ";} cout<<'\n';
	#endif
	
	// Subtask 2
	pair<int,int> a[n];
	int _ptr=0;
	for(int i=0;i<26;++i){
		if(v[i].size()){
			a[_ptr++]={v[i][0],i};
		}
	}
	sort(a,a+n);
	int word[n];
	for(int i=0;i<n;++i)
		word[i]=a[i].second;
	
	int ans=0;
	for(int i=0;i<n;++i){
		int x=v[word[i]][0];
		int pos=x+sum(x);
		ans+=max(pos-i,0ll);
		add(i,1),add(x,-1);
	}
	for(int i=0;i<n;++i){
		int x=v[word[i]][1];
		int pos=x+sum(x);
		ans+=max(pos-n-i,0ll);
		add(i+n,1),add(x,-1);
	}
	cout<<ans<<'\n';
	/*
	for(int i=0;i<26;++i) if(v[i].size()) {
		int x=min(v[i][0],pos[i]),y=max(v[i][0],pos[i]);
		ans+=y-x-sum(x,y);
		cout<<x<<" "<<y<<" -> "<<sum(x,y)<<'\n';
		add(v[i][0],1);
		
		x=min(v[i][1],pos[i]+n),y=max(v[i][1],pos[i]+n);
		ans+=y-x-sum(x,y);
		cout<<x<<" "<<y<<" -> "<<sum(x,y)<<'\n';
		add(v[i][1],1);
	}
	cout<<ans<<'\n';*/
	return 0;

	// Subtask 1
	int cnt=0;
	for(int i=0;i<26;++i)
		if(v[i].size()) ++cnt;
	if(cnt==2){
		cout<<(n/2)*(n/2)<<'\n';
		return 0;
	}
	return 0;
}

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