//gm --- akezhon
#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #define int long long
#define pb push_back
#define F first
#define S second
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define tm (tl+tr)/2
#define TL v+v, tl, tm
#define TR v+v+1, tm+1, tr
#define DA l <= tl && tr <= r
#define NET r < tl || tr < l
#define double long double
using namespace std;
const int N=2e7+7;
const int M=1e9+7;
const int NN=2e5+7;
const int inf=1e9;
int c[N], tin[N], tout[N], eul[N], sz[N], big[N], t[N*4], l[N], r[N], szz;
vector <pair<int*, int>> rb;
int n, timer, cur, ans;
void roll(int &x){
rb.push_back({&x, x});
}
void tupd(int pos, int v=1, int tl=1, int tr=n){
roll(t[v]);
if(tl == tr){
t[v]++;
return;
}
if(pos <= tm)tupd(pos, TL);
else tupd(pos, TR);
t[v] = t[v+v] + t[v+v+1];
}
int get(int l, int r, int v=1, int tl=1, int tr=n){
if(NET)return 0;
if(DA)return t[v];
return get(l, r, TL) + get(l, r, TR);
}
void dfs(int v=1){
if(cnt[v])timer++;
tin[v] = timer;
eul[timer] = v;
sz[v] = 1;
if(!c[v]){
dfs(l[v]);
dfs(r[v]);
sz[v] += sz[l[v]];
sz[v] += sz[r[v]];
if(sz[r[v]] > sz[l[v]])big[v] = r[v];
else big[v] = l[v];
}
tout[v] = timer;
}
void go(int v=1, int cl=0){
int temp = rb.size();
if(!c[v]){
if(big[v] == l[v])go(r[v], 1);
else go(l[v], 1);
go(big[v], 0);
int cntkeep=0, cntswap=0;
if(big[v] == l[v]){
for(int i=tin[r[v]]; i <= tout[r[v]]; i++){
int f = eul[i];
if(c[f]){
cntkeep += get(c[f], n);
cntswap += get(1, c[f]);
}
}
if(!cl) {
for(int i=tin[r[v]]; i <= tout[r[v]]; i++){
int f = eul[i];
if(c[f]){
tupd(c[f]);
}
}
}
}
else {
for(int i=tin[l[v]]; i <= tout[l[v]]; i++){
int f = eul[i];
if(c[f]){
cntkeep += get(1, c[f]);
cntswap += get(c[f], n);
}
}
if(!cl){
for(int i=tin[l[v]]; i <= tout[l[v]]; i++){
int f = eul[i];
if(c[f]){
tupd(c[f]);
}
}
}
}
ans += min(cntkeep, cntswap);
if(cl){
while(temp < (int)rb.size()){
*(rb.back().F) = rb.back().S;
rb.pop_back();
}
}
}
else {
if(!cl)tupd(c[v]);
}
}
void rec(){
cin >> c[szz];
if(!c[szz]){
int cur = szz;
szz++;
l[cur] = szz;
rec();
szz++;
r[cur] = szz;
rec();
}
}
void AlemAmenov(){
cin >> n;
szz=1;
rec();
dfs();
go();
cout << ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
// freopen("promote.in", "r", stdin);
// freopen("promote.out", "w", stdout);
int RealName=1;
// cin >> RealName;
// int C=0;
while(RealName--){
// cout << "Case " << ++C << ":\n";
AlemAmenov();
}
return 0;
}
Compilation message
rot.cpp: In function 'void dfs(int)':
rot.cpp:44:4: error: 'cnt' was not declared in this scope; did you mean 'int'?
44 | if(cnt[v])timer++;
| ^~~
| int
