Submission #697288

#	Time	Username	Problem	Language	Result	Execution time	Memory
697288		Baytoro	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	104 ms	57164 KiB

shoes

#include <bits/stdc++.h>
//#include "shoes.h"
using namespace std;
#define ios ios::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL);
#define pb push_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fr first
#define sc second
#define endl '\n'
#define ll long long
//#define int long long
void fopn(string name){
    freopen((name+".in").c_str(),"r",stdin);
    freopen((name+".out").c_str(),"w",stdout);
}
const int N=1e6+5;
int bit[N];
void update(int i, int v){
	for(;i<=N;i+=i&-i){
		bit[i]+=v;
	}
}
ll query(int i){
	int res=0;
	for(;i>0;i-=i&-i) res+=bit[i];
	return res; 
}
ll query(int l, int r){
	return query(r)-query(l-1);
}
vector<int> a[N][2];
ll count_swaps(vector<int> s){
	int n=s.size();
	for(int i=1;i<=n;i++){
		update(i,1);
		a[abs(s[i-1])][s[i-1]<0].pb(i);
	}
	ll res=0;
	for(int i=1;i<=n;i++) for(int j=0;j<2;j++) reverse(all(a[i][j]));
	for(int i=1;i<=n;i++){
		if(!s[i-1]) continue;
		int x=s[i-1],y=(s[i-1]<0),z=a[abs(x)][y^1].back();
		a[abs(x)][0].pop_back();
		a[abs(x)][1].pop_back();
		s[z-1]=0;
		s[i-1]=0;
		update(z,-1);
		if(y) res+=query(i+1,z);
		else res+=query(i,z);
	}
	return res;
}
/*void solve(){
	int n;cin>>n;
	vector<int> vec(n);
	for(int i=0;i<n;i++)
		cin>>vec[i];
	cout<<count_swaps(vec);
}
main(){
    ios;
    int T=1;
    //cin>>T;
    while(T--){
        solve();
    }
}*/

Compilation message (stderr)

shoes.cpp: In function 'void fopn(std::string)':
shoes.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen((name+".in").c_str(),"r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
shoes.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((name+".out").c_str(),"w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15