Submission #1003781

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003781		vjudge1	Ekoeko (COCI21_ekoeko)	C++17	10 / 110	7 ms	2704 KiB

Main

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

#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define mp make_pair
#define int long long

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef complex<double> cd;

const int MAXN = 1e5+10;
const int MOD = 1e9+7;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3f;
const double PI = acos(-1);

int tree[MAXN];

void upd(int pos, int x, int lim){ for(;pos<=lim;pos+=(pos&-pos)) tree[pos]+=x; }
int query(int pos){
	int ret=0;
	for(;pos>0;pos-=(pos&-pos)) ret+=tree[pos];
	return ret;
}

void solve(){
	int n; cin >> n;
	string s; cin >> s;
	
	vector<int> freq(26, 0);
	for(auto u : s) freq[(int)(u-'a')]++;
	
	string s1="", s2="";
	int ans=0, tot=0;
	vector<int> occ(26, 0);
	for(auto u : s){
		occ[(int)(u-'a')]++;
		
		if(occ[(int)(u-'a')]>(freq[(int)(u-'a')]>>1)){
			tot++;
			s2+=u;
		}
		else{
			ans+=tot;
			s1+=u;
		}
	}
	
	int lim=(int)s2.size();
	
	vector<queue<int>> id(26);
	for(int i=0;i<(int)s2.size();i++) id[(int)(s2[i]-'a')].push(i+1);
	
	for(int i=1;i<=(int)s2.size();i++) upd(i, i, lim), upd(i+1, -i, lim);
	
	for(int i=1;i<=(int)s1.size();i++){
		int curr=id[(int)(s1[i-1]-'a')].front();
		id[(int)(s1[i-1]-'a')].pop();
		ans+=max(query(curr)-i, 0ll);
		upd(i, 1, lim);
		upd(curr+1, -1, lim);
	}
	
	cout << ans << "\n";
}

int32_t main(){
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	
	int tt=1;
	//~ cin >> tt;
	while(tt--) solve();
	return 0;
}

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