#include <bits/stdc++.h>
using namespace std;
const int MAXN = 500000;
struct BIT {
vector<int> tree;
int n;
void init(int _n) {
n = _n;
tree.assign(n+1,0);
}
void update(int pos,int val) {
for (;pos <= n;pos += pos & -pos) tree[pos] += val;
}
int query(int pos) {
int sum = 0;
for (;pos > 0;pos -= pos & -pos) sum += tree[pos];
return sum;
}
int query(int l,int r) {
if (l > r) return 0;
return query(r) - query(l-1);
}
} tree;
vector<int> adj[MAXN+1];
stack<pair<int,int>> st;
vector<int> ch[MAXN+1];
int val[MAXN+1];
int sz[MAXN+1];
int n;
int cnt;
long long ans = 0;
int cal_sz(int u) {
if (adj[u].size() == 0) return sz[u] = 1;
sz[u] += cal_sz(adj[u][0]);
sz[u] += cal_sz(adj[u][1]);
return sz[u];
}
void dfs(int u,int keep) {
if (adj[u].size() == 0) {
ch[u].push_back(val[u]);
if (keep) tree.update(val[u],1);
return;
}
int lt = adj[u][0], rt = adj[u][1];
long long tmp = 0;
if (sz[lt] < sz[rt]) {
dfs(lt,0);
dfs(rt,1);
ch[u].swap(ch[rt]);
for (int i=0;i<ch[lt].size();i++) {
int v = ch[lt][i];
ch[u].push_back(v);
// cerr << u << ' ' << v << '\n';
tmp += tree.query(1,v-1);
}
for (int i=0;i<ch[lt].size();i++) tree.update(ch[lt][i],1);
}
else {
dfs(rt,0);
dfs(lt,1);
ch[u].swap(ch[lt]);
for (int i=0;i<ch[rt].size();i++) {
int v = ch[rt][i];
// cerr << u << ' ' << v << '\n';
ch[u].push_back(v);
tmp += tree.query(v+1,n);
}
for (int i=0;i<ch[rt].size();i++) tree.update(ch[rt][i],1);
}
tmp = min(tmp,1ll * sz[lt] * sz[rt] - tmp);
ans += tmp;
if (!keep) {
for (int i=0;i<ch[u].size();i++) tree.update(ch[u][i],-1);
}
}
int main() {
cin.tie(0) -> sync_with_stdio(0);
cin >> n;
tree.init(n);
for (int i=1;;i++) {
cin >> val[i];
if (st.size()) adj[st.top().first].push_back(i);
if (st.size()) {
st.top().second++;
if (st.top().second == 2) st.pop();
}
if (val[i] == 0) {
st.push({i,0});
}
else cnt++;
if (cnt == n) break;
}
cal_sz(1);
dfs(1,1);
cout << ans;
return 0;
}
Compilation message
rot.cpp: In function 'void dfs(int, int)':
rot.cpp:56:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
56 | for (int i=0;i<ch[lt].size();i++) {
| ~^~~~~~~~~~~~~~
rot.cpp:62:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
62 | for (int i=0;i<ch[lt].size();i++) tree.update(ch[lt][i],1);
| ~^~~~~~~~~~~~~~
rot.cpp:68:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
68 | for (int i=0;i<ch[rt].size();i++) {
| ~^~~~~~~~~~~~~~
rot.cpp:74:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
74 | for (int i=0;i<ch[rt].size();i++) tree.update(ch[rt][i],1);
| ~^~~~~~~~~~~~~~
rot.cpp:79:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
79 | for (int i=0;i<ch[u].size();i++) tree.update(ch[u][i],-1);
| ~^~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
27472 KB |
Output is correct |
2 |
Correct |
5 ms |
27472 KB |
Output is correct |
3 |
Correct |
5 ms |
27472 KB |
Output is correct |
4 |
Correct |
5 ms |
27692 KB |
Output is correct |
5 |
Correct |
5 ms |
27472 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
27472 KB |
Output is correct |
2 |
Correct |
5 ms |
27472 KB |
Output is correct |
3 |
Correct |
5 ms |
27472 KB |
Output is correct |
4 |
Correct |
6 ms |
27472 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
27728 KB |
Output is correct |
2 |
Correct |
6 ms |
27580 KB |
Output is correct |
3 |
Correct |
6 ms |
27728 KB |
Output is correct |
4 |
Correct |
5 ms |
27832 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
28240 KB |
Output is correct |
2 |
Correct |
8 ms |
27984 KB |
Output is correct |
3 |
Correct |
8 ms |
28240 KB |
Output is correct |
4 |
Correct |
8 ms |
28496 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
11 ms |
29776 KB |
Output is correct |
2 |
Correct |
13 ms |
29008 KB |
Output is correct |
3 |
Correct |
29 ms |
31048 KB |
Output is correct |
4 |
Correct |
12 ms |
29632 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
40 ms |
32600 KB |
Output is correct |
2 |
Correct |
31 ms |
34636 KB |
Output is correct |
3 |
Correct |
33 ms |
36176 KB |
Output is correct |
4 |
Correct |
34 ms |
36168 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
40 ms |
42436 KB |
Output is correct |
2 |
Correct |
43 ms |
39752 KB |
Output is correct |
3 |
Correct |
49 ms |
37892 KB |
Output is correct |
4 |
Correct |
45 ms |
36044 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
56 ms |
37356 KB |
Output is correct |
2 |
Correct |
54 ms |
40012 KB |
Output is correct |
3 |
Correct |
58 ms |
44376 KB |
Output is correct |
4 |
Correct |
55 ms |
44016 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
144 ms |
48628 KB |
Output is correct |
2 |
Correct |
99 ms |
46532 KB |
Output is correct |
3 |
Correct |
84 ms |
45668 KB |
Output is correct |
4 |
Correct |
103 ms |
45632 KB |
Output is correct |
5 |
Correct |
145 ms |
46656 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
91 ms |
44540 KB |
Output is correct |
2 |
Correct |
100 ms |
54300 KB |
Output is correct |
3 |
Correct |
109 ms |
51664 KB |
Output is correct |
4 |
Correct |
93 ms |
55112 KB |
Output is correct |
5 |
Correct |
182 ms |
49732 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
103 ms |
45228 KB |
Output is correct |
2 |
Correct |
87 ms |
47552 KB |
Output is correct |
3 |
Correct |
144 ms |
47724 KB |
Output is correct |
4 |
Correct |
112 ms |
47048 KB |
Output is correct |
5 |
Correct |
105 ms |
54724 KB |
Output is correct |
6 |
Correct |
212 ms |
50628 KB |
Output is correct |