Submission #1003784

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003784		vjudge1	Ekoeko (COCI21_ekoeko)	C++17	20 / 110	28 ms	16152 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
const int maxn = 2e5+5;

int bit[maxn];

void upd(int x){
	for(; x<maxn; x+=x&-x) bit[x]++;
}

int query(int x){
	int rt=0;
	for(; x>0; x-=x&-x) rt+=bit[x];
	return rt;
}

signed main(){
	int n; cin >> n;
	string s; cin >> s;
	map<char,int> mp, cnt;
	for(char c : s) cnt[c]++;

	int cnt1=0, cnt2=0;
	vector<int> arr1, arr2;
	vector<int> trans(2*n);
	map<char,set<int>> pos;
	for(int i=0; i<2*n; i++){
		if(mp[s[i]]<cnt[s[i]]/2){
			mp[s[i]]++;
			cnt1++;
			trans[i]=cnt1;
			pos[s[i]].insert(i+1);
		}
	}
	for(int i=0; i<2*n; i++) if(!trans[i]){
		assert(pos[s[i]].size()>0);
		trans[i] = (*pos[s[i]].begin())+n;
		pos[s[i]].erase(pos[s[i]].begin());
	}

	// for(int x : trans) cout << x << " ";
	// cout << endl;

	int ans=0;
	for(int i=0; i<2*n; i++){
		ans += i-query(trans[i]-1);
		upd(trans[i]);
	}
	cout << ans << '\n';
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:25:14: warning: unused variable 'cnt2' [-Wunused-variable]
   25 |  int cnt1=0, cnt2=0;
      |              ^~~~

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