Submission #155990

#	Time	Username	Problem	Language	Result	Execution time	Memory
155990		GioChkhaidze	Arranging Shoes (IOI19_shoes)	C++14	Compilation error	0 ms	0 KiB

shoes

#include "shoes.h"
using namespace std;
const int N=200005;
long long a[2*N],G[2*N],s[2*N],n;
vector < long long > f1[2*N],f2[2*N]; 
 
void Upd(long long x,long long dl) {
	while (x<=2*N) {
		G[x]+=dl;
		x+=(x & -x);
	}
}
 
long long Get(long long x) {
	long long res=0;
	while (0<x) {
		res+=G[x];
		x-=(x & -x);
	}
	return res;
}

long long count_swaps(std::vector<int> s) {
	long long ans=0;
    long long n=s.size();
  
	for (int i=0; i<n; i++) {
		a[i+1]=s[i];
		if (a[i+1]>0) f1[a[i+1]].push_back(i+1);
		if (a[i+1]<0) f2[-a[i+1]].push_back(i+1);
		Upd(i+1,1);
	}
	
	for (int i=0; i<n; i++)
		reverse(f1[i].begin(),f1[i].end()),
		reverse(f2[i].begin(),f2[i].end());
	
	for (int i=1; i<=n/2; i++) {
		long long l=1,r=n,mid,idx=-1;
		
		while (l<=r) {
			mid=(l+r)/2;
			if (1<=Get(mid)) { idx=mid; r=mid-1; } 
								   else l=mid+1;
		}

		if (a[idx]<0) {
			long long x=-a[idx];
			ans+=Get(f1[x].back()-1)-1;

			Upd(idx,-1);
			Upd(f1[x].back(),-1);
			f1[x].pop_back();
			f2[x].pop_back();
		}
			else {
			long long x=a[idx];
			ans+=Get(f2[x].back()-1);
			Upd(idx,-1);
			Upd(f2[x].back(),-1);
			f1[x].pop_back();
			f2[x].pop_back();
		}
	}

	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:35:3: error: 'reverse' was not declared in this scope
   reverse(f1[i].begin(),f1[i].end()),
   ^~~~~~~