#include "shoes.h" #include <set> using namespace std; #define ll long long set<int> shoes[200000]; int n; int dist[200000]; ll get_dist(int idx){ ll d=0; for(int i=0;i<idx;i++) d+=dist[i]; return d; } ll count_swaps(vector<int> s) { n = s.size(); for(int i=0;i<n;i++) shoes[s[i]+100000].insert(i); for(int i=0;i<n;i++) dist[i]=1; ll res=0; int pos1=0; while(pos1<n){ int pos2=*shoes[100000-s[pos1]].begin(); res+=get_dist(pos2); if(s[pos1]<0) res--; dist[pos1]=0; dist[pos2]=0; shoes[100000-s[pos1]].erase(shoes[100000-s[pos1]].begin()); shoes[100000+s[pos1]].erase(shoes[100000+s[pos1]].begin()); while(dist[pos1]==0) pos1++; } return res; }