#include <bits/stdc++.h>
#include "shoes.h"
using namespace std;
// #define int long long
#define ll long long
#define ff first
#define ss second
#define pint pair < int , int >
#define fast ios_base::sync_with_stdio(NULL); cin.tie(NULL)
const int inf = 1e9 + 9;
const int mxn = 2e5 + 2;
const int mod = 1e9 + 7;
ll fn[mxn];
void update(int x , int v) {
for (; x < mxn; x += x&-x) {
fn[x] += v;
}
}
ll query(int l , int r) {
ll ans = 0;
l--;
for (; r > 0; r -= r&-r) ans += fn[r];
for (; l > 0; l -= l&-l) ans -= fn[l];
return ans;
}
queue < ll > le[mxn] , ri[mxn];
bool b[mxn];
ll count_swaps(vector < ll > v) {
ll n = v.size() / 2;
for (ll i = 0; i < 2*n; i++) {
if (v[i] < 0) le[-v[i]].push(i);
else ri[v[i]].push(i);
update(i+1 , 1);
}
ll ans = 0;
for (ll i = 0; i < 2*n; i++) {
if (b[i]) continue;
ll id;
if (v[i] < 0) {
id = ri[-v[i]].front();
ans += query(i+2 , id);
update(id+1 , -1);
} else {
id = le[v[i]].front();
ans += query(i+2 , id) + 1;
update(id+1 , -1);
}
ri[abs(v[i])].pop();
le[abs(v[i])].pop();
b[id] = 1;
}
return ans;
}
Compilation message
/usr/bin/ld: /tmp/ccnMQjnB.o: in function `main':
grader.cpp:(.text.startup+0x29d): undefined reference to `count_swaps(std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status
