#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
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()),
^~~~~~~
