#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<vector<int>> g(n);
vector<int> l(n);
vector<int> e(n);
for (int i = 0; i < n; i++) {
int j;
cin >> j >> l[i];
j--;
e[i] = j;
g[i].emplace_back(i);
g[j].emplace_back(i);
}
for (int i = 0; i < n; i++) {
if (e[e[i]] == i) {
l[e[i]] = l[i] = max(l[e[i]], l[i]);
}
}
long long ans = 0;
vector<int> was(n);
vector<int> pv(n);
vector<int> cycle(n);
vector<int> last_id(n);
vector<vector<long long>> c(n);
for (int i = 0; i < n; i++) {
if (was[i]) {
continue;
}
int c1 = -1, c2 = -1;
int sz = 0;
int dead = -1;
pv[i] = -1;
set<int> vs;
{ // dfs1
stack<pair<int, int>> stk;
stk.emplace(i, -1);
while (!stk.empty()) {
auto [v, pe] = stk.top();
vs.emplace(v);
was[v] = 1;
debug(v);
if (last_id[v] == (int) g[v].size()) {
for (auto id : g[v]) {
int to = v ^ id ^ e[id];
if (to == pv[v]) {
continue;
}
cycle[v] += cycle[to];
}
if (v == c1 || v == c2) {
cycle[v] = 1;
}
sz += cycle[v];
stk.pop();
continue;
}
int &gid = last_id[v];
while (gid < (int) g[v].size()) {
int id = g[v][gid++];
if (id == pe) {
continue;
}
int to = v ^ id ^ e[id];
if (was[to]) {
debug(v, to);
if (c1 != -1) {
continue;
}
dead = id;
c1 = v;
c2 = to;
cycle[v]++;
if (pv[to] != -1) {
cycle[pv[to]]--;
}
continue;
}
pv[to] = v;
stk.emplace(to, id);
break;
}
}
}
vector<long long> d1(sz + 1), d2(sz + 1);
for (int z = 0; z < 2; z++) {
queue<tuple<int, int, int, long long>> que;
que.emplace(c1, c2, 0, 0);
while (!que.empty()) {
auto [v, p, cnt, now] = que.front();
que.pop();
cnt += cycle[v];
d1[cnt] = max(d1[cnt], now);
for (auto id : g[v]) {
int to = v ^ id ^ e[id];
if (to == p || id == dead) {
continue;
}
que.emplace(to, v, cnt, now + l[id]);
}
};
// dfs2(c1, c2, 0, 0);
swap(c1, c2);
swap(d1, d2);
}
for (int j = 0; j < sz; j++) {
d1[j + 1] = max(d1[j + 1], d1[j]);
d2[j + 1] = max(d2[j + 1], d2[j]);
}
long long t = 0;
for (int z = 0; z < 2; z++) {
for (int v : vs) {
last_id[v] = 0;
c[v].clear();
}
stack<tuple<int, int, long long>> stk;
stk.emplace(c1, c2, 0);
while (!stk.empty()) {
auto [v, p, now] = stk.top();
t = max(t, now);
if (last_id[v] == (int) g[v].size()) {
stk.pop();
if (c[v].empty()) {
if (p != c2) {
c[p].emplace_back(now);
}
continue;
}
sort(c[v].rbegin(), c[v].rend());
if (c[v].size() > 1) {
t = max(t, c[v][0] + c[v][1] - 2 * now);
}
if (p != c2) {
c[p].emplace_back(c[v][0]);
}
continue;
}
int &gid = last_id[v];
while (gid < (int) g[v].size()) {
int id = g[v][gid++];
int to = v ^ id ^ e[id];
if (to == p || id == dead) {
continue;
}
stk.emplace(to, v, now + l[id]);
c[v].emplace_back();
}
};
swap(c1, c2);
}
debug(t);
debug(d1);
debug(d2);
for (int j = 1; j < sz; j++) {
t = max(t, d1[j] + d2[sz - j] + l[dead]);
}
ans += t;
}
cout << ans << '\n';
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
0 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
1 ms |
332 KB |
Output is correct |
| 4 |
Correct |
0 ms |
204 KB |
Output is correct |
| 5 |
Correct |
0 ms |
204 KB |
Output is correct |
| 6 |
Correct |
0 ms |
204 KB |
Output is correct |
| 7 |
Correct |
0 ms |
204 KB |
Output is correct |
| 8 |
Correct |
0 ms |
204 KB |
Output is correct |
| 9 |
Correct |
0 ms |
204 KB |
Output is correct |
| 10 |
Correct |
0 ms |
332 KB |
Output is correct |
| 11 |
Correct |
0 ms |
204 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
460 KB |
Output is correct |
| 2 |
Correct |
1 ms |
460 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
2 ms |
460 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
16 ms |
2396 KB |
Output is correct |
| 2 |
Correct |
43 ms |
7136 KB |
Output is correct |
| 3 |
Correct |
25 ms |
3944 KB |
Output is correct |
| 4 |
Incorrect |
11 ms |
1980 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
56 ms |
9976 KB |
Output is correct |
| 2 |
Correct |
79 ms |
13764 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
198 ms |
36244 KB |
Output is correct |
| 2 |
Correct |
212 ms |
38608 KB |
Output is correct |
| 3 |
Correct |
248 ms |
49672 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
315 ms |
52412 KB |
Output is correct |
| 2 |
Correct |
447 ms |
97560 KB |
Output is correct |
| 3 |
Correct |
517 ms |
102572 KB |
Output is correct |
| 4 |
Correct |
602 ms |
125308 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
601 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
357 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
