#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;
vector<pair<int, ll>> graph[1010101], cycle;
ll discarded, ans = 0, cmp_ans, dp[1010101], p[5][1010101];
int cycle_start;
bool processed[1010101], visited[1010101], on_cycle[1010101], adding = false;
void find_cycle(int node, pair<int, ll> parent = {0, 0}) {
if (visited[node]) {
cycle_start = node;
cycle.push_back({node, 0});
cycle.push_back(parent);
adding = true;
return;
}
visited[node] = true;
for (pair<int, ll> i : graph[node]) if (i != parent) {
find_cycle(i.first, {node, i.second});
if (cycle_start) {
if (node == cycle_start) adding = false;
if (adding) cycle.push_back(parent);
return;
}
}
}
void calc_tree(int node, int parent = 0) {
processed[node] = true;
ll mx = 0, sc = 0;
for (pair<int, ll> i : graph[node]) if (i.first != parent && !on_cycle[i.first]) {
calc_tree(i.first, node);
if (dp[i.first] + i.second > mx) sc = mx, mx = dp[i.first] + i.second;
else if (dp[i.first] + i.second > sc) sc = dp[i.first] + i.second;
}
dp[node] = mx;
cmp_ans = max(cmp_ans, mx + sc);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
FOR(i, 1, n + 1) {
int v;
ll l;
cin >> v >> l;
graph[i].push_back({v, l});
graph[v].push_back({i, l});
}
FOR(i, 1, n + 1) if (!processed[i]) {
cycle.clear();
cycle_start = 0;
find_cycle(i);
discarded = cycle.back().second;
cycle.pop_back();
for (pair<int, ll> j : cycle) on_cycle[j.first] = true;
cmp_ans = 0;
int m = cycle.size();
FOR(j, 1, m) p[0][j] = p[0][j - 1] + cycle[j].second;
for (int j = m - 2; ~j; j--) p[1][j] = p[1][j + 1] + cycle[j + 1].second;
FOR(j, 0, m) {
calc_tree(cycle[j].first);
p[2][j] = dp[cycle[j].first] - p[0][j];
p[3][j] = dp[cycle[j].first] + p[0][j];
p[4][j] = dp[cycle[j].first] + p[1][j];
}
ll mx = p[2][0];
FOR(j, 1, m) {
cmp_ans = max(cmp_ans, p[3][j] + mx);
mx = max(mx, p[2][j]);
}
mx = p[4][m - 1];
for (int j = m - 2; ~j; j--) {
cmp_ans = max(cmp_ans, p[3][j] + mx + discarded);
mx = max(mx, p[4][j]);
}
ans += cmp_ans;
FOR(j, 0, 5) FOR(k, 0, m) p[j][k] = 0;
}
cout << ans;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
18 ms |
24064 KB |
Output is correct |
2 |
Correct |
18 ms |
24192 KB |
Output is correct |
3 |
Correct |
18 ms |
24192 KB |
Output is correct |
4 |
Correct |
19 ms |
24064 KB |
Output is correct |
5 |
Correct |
19 ms |
24064 KB |
Output is correct |
6 |
Correct |
19 ms |
24064 KB |
Output is correct |
7 |
Correct |
19 ms |
24064 KB |
Output is correct |
8 |
Correct |
18 ms |
24168 KB |
Output is correct |
9 |
Correct |
18 ms |
24064 KB |
Output is correct |
10 |
Correct |
19 ms |
24192 KB |
Output is correct |
11 |
Correct |
19 ms |
24192 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
19 ms |
24320 KB |
Output is correct |
2 |
Correct |
19 ms |
24192 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
20 ms |
24320 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
26 ms |
25728 KB |
Output is correct |
2 |
Correct |
37 ms |
29172 KB |
Output is correct |
3 |
Correct |
29 ms |
25848 KB |
Output is correct |
4 |
Correct |
23 ms |
24960 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
43 ms |
30704 KB |
Output is correct |
2 |
Correct |
62 ms |
33392 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
111 ms |
39792 KB |
Output is correct |
2 |
Correct |
117 ms |
49000 KB |
Output is correct |
3 |
Correct |
144 ms |
62952 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
177 ms |
51496 KB |
Output is correct |
2 |
Correct |
234 ms |
85860 KB |
Output is correct |
3 |
Correct |
259 ms |
97992 KB |
Output is correct |
4 |
Correct |
329 ms |
131072 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
380 ms |
81196 KB |
Output is correct |
2 |
Runtime error |
618 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
437 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
2 |
Halted |
0 ms |
0 KB |
- |