Submission #875516

#	Time	Username	Problem	Language	Result	Execution time	Memory
875516		Ahmed_Solyman	Ekoeko (COCI21_ekoeko)	C++14	0 / 110	1 ms	604 KiB

Main

/*
In the name of Allah
made by: Ahmed_Solyman
*/
#include <bits/stdc++.h>
#include <ext/rope>
 
using namespace std;
using namespace __gnu_cxx;
#pragma GCC optimize("-Ofast")
#pragma GCC optimize("-O1")
//-------------------------------------------------------------//
typedef long long ll;
typedef unsigned long long ull;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PI acos(-1)
#define lb lower_bound
#define ub upper_bound
#define endl '\n'
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define sum_to(n) (n*(n+1))/2
#define pb push_back
#define pf push_front
#define fil(arr,x) memset(arr,x,sizeof(arr))
const ll mod=1e9+7;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,-1,1};
//-------------------------------------------------------------//
ll lcm(ll a,ll b)
{
    return (max(a,b)/__gcd(a,b))*min(a,b);
}
void person_bool(bool x)
{
    cout<<(x?"YES":"NO")<<endl;
}
struct BIT{
    vector<int>bit;
    int n;
    void init(int _n){
        bit.assign(_n+5,0LL);
        n=_n;
    }
    void add(int i,int v){
        while(i<=n)bit[i]+=v,i+=i&(-i);
    }
    int sum(int i){
        int ret=0;
        while(i)ret+=bit[i],i-=i&(-i);
        return ret;
    }
    int query(int l,int r){
        return sum(r)-sum(l-1);
    }
}b;
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    #ifndef ONLINE_JUDGE
    //freopen("input.in", "r", stdin);
    //freopen("output.out", "w", stdout);
    #endif
    fast
    int n;cin>>n;
    string s;cin>>s;
    vector<int>v[26];
    for(int i=0;i<n*2;i++){
        v[s[i]-'a'].push_back(i+1);
    }
    vector<int>f(n+5);
    for(int i=0;i<26;i++){
        for(int j=0;j<(int)v[i].size()/2;j++){
            f[v[i][j]]=v[i][j+(int)v[i].size()/2]-n;
        }
    }
    b.init(n);
    ll ans=0;
    for(int i=n;i>=1;i--){
        assert(f[i]>0);
        ans+=b.sum(f[i]);
        b.add(f[i],1);
    }
    cout<<ans<<endl;
    return 0;
}

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