# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
306313 | tengiz05 | Arranging Shoes (IOI19_shoes) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "shoes.h"
#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
struct segtree{
vector<int> t;
int sz;
void init(int n){
sz = 1;
while(sz < n)sz *= 2;
t.assign(sz*2, 1);
for(int i=sz-1; i>0; i--)t[i] = t[i*2] + t[i*2+1];
}
void add(int pos, int val){
pos += sz;
t[pos] += val;
for(;pos > 1; pos>>=1)t[pos>>1] = t[pos] + t[pos^1];
}
int query(int l, int r){
if(l > r)return 0;
l += sz, r += sz;
int sum = 0;
for(;l <= r; l>>=1, r>>=1){
if(l%2 == 1)sum += t[l], l++;
if(r%2 == 0)sum += t[r], r--;
}return sum;
}
};
long long count_swaps(vector<int> a) {
int n = a.size()/2;
long long ans = 0;
vector<vector<int>> pos(n+1);
vector<vector<int>> neg(n+1);
for(int i=0;i<n*2;i++){
if(a[i] > 0)
pos[a[i]].push_back(i);
else
neg[abs(a[i])].push_back(i);
}
for(int i=1;i<=n;i++){
sort(pos[i].begin(), pos[i].end());
sort(neg[i].begin(), neg[i].end());
}
vector<pair<int, int>> need;
for(int i=1;i<=n;i++){
for(int j=0;j<pos[i].size();j++){
int r = pos[i][j];
int l = neg[i][j];
if(l > r)swap(l, r),ans++;
need.push_back({l, r});
}
}
sort(need.begin(), need.end());
segtree seg;
seg.init(n*2);
for(auto X : need){
int l = X.first;
int r = X.second;
ans += (long long)max(0, seg.query(l+1, r-1));
// cout << l << ' ' << r << ';' << seg.query(l+1, r-1) << '\n';
seg.add(l, -1);
seg.add(r, -1);
}
//cout << "; ans = " << ans << '\n';
return ans;
}
/*
3
-2 -2 -2 2 2 2
3
-2 2 2 -2 -2 2
2
2 1 -1 -2
*/