제출 #824491

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
824491		yusuf12360	Ekoeko (COCI21_ekoeko)	C++14	110 / 110	16 ms	3572 KiB

Main

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n;
int merge(vector<int> &a, int l, int r);
int number_of_inversions(vector<int> &a, int l=0, int r=n-1) {
	if(l>=r) return 0;
	int mid=l+r>>1, ret=0;
	ret+=number_of_inversions(a, l, mid);
	ret+=number_of_inversions(a, mid+1, r);
	ret+=merge(a, l, r);
	return ret;
}
int merge(vector<int> &a, int l, int r) {
	vector<int> temp(r-l+1);
	int mid=l+r>>1;
	int i=l, j=mid+1, k=0, ret=0;
	while(i<=mid && j<=r) {
		if(a[i]<=a[j]) temp[k++]=a[i++];
		else temp[k++]=a[j++], ret+=mid-i+1;
	}
	while(i<=mid) temp[k++]=a[i++];
	while(j<=r) temp[k++]=a[j++];
	for(int I=l; I<=r; I++) a[I]=temp[I-l];
	return ret;
}
signed main() {
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	string s; 
	cin >> n >> s;
	vector<int> a, cnt(26);
	vector<deque<int>> idx(26);
	vector<bool> vis(2*n);
	for(char c : s) cnt[c-'a']++;
	for(int &p : cnt) p>>=1;
	int ans=0, pre=0;
	for(int i=0; i<2*n; i++) {
		if(cnt[s[i]-'a']) {
			cnt[s[i]-'a']--;
			vis[i]=1;
			idx[s[i]-'a'].push_back(i);
			ans+=pre;
		} else pre++;
	}
	for(int i=0; i<2*n; i++) {
		if(vis[i]) continue;
		a.push_back(idx[s[i]-'a'].front());
		idx[s[i]-'a'].pop_front();
	}
	ans+=number_of_inversions(a);
	cout << ans << '\n';
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'long long int number_of_inversions(std::vector<long long int>&, long long int, long long int)':
Main.cpp:8:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    8 |  int mid=l+r>>1, ret=0;
      |          ~^~
Main.cpp: In function 'long long int merge(std::vector<long long int>&, long long int, long long int)':
Main.cpp:16:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   16 |  int mid=l+r>>1;
      |          ~^~

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