#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef TEST
#define getchar_unlocked _getchar_nolock
#endif
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef double db;
typedef long long ll;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tree<pair<int, int>, null_type, less<pair<int, int> >, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef tree<pair<int, int>, null_type, less<pair<int, int> >, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
ll ans, L, ed, le[1000005], lpath[1000005], ldpath[1000005], pref[1000005];
int N, U, st, rn, link[1000005], sz[1000005], ign[1000005];
bool oncyc[1000005], vis[1000005];
vector<int> comp, path[1000005];
vector<ll> wt[1000005];
vector<tuple<int, ll, int> > adj[1000005];
int find(int x) {
if (x == link[x]) return x;
return link[x] = find(link[x]);
}
void unite(int a, int b) {
a = find(a);
b = find(b);
if (a == b) return;
if (sz[b] > sz[a]) swap(a, b);
sz[a] += sz[b];
link[b] = a;
}
void dfs(int n, int e = -1) {
vis[n] = 1;
for (auto u : adj[n])
if (g2(u) != e) {
if (vis[g0(u)]) {
st = g0(u);
ed = n;
ign[find(n)] = g2(u);
le[find(n)] = g1(u);
return;
}
dfs(g0(u), n);
}
}
bool find_path(int n) {
if (n == ed) {
path[find(n)].pb(n);
oncyc[n] = 1;
return 1;
}
for (auto u : adj[n])
if (g2(u) != ign[find(n)] && find_path(g0(u))) {
path[find(n)].pb(n);
wt[find(n)].pb(g1(u));
oncyc[n] = 1;
return 1;
}
return 0;
}
void find_diam(int n, int e = -1, int d = 0) {
if (d > ed) {
ed = d;
st = n;
}
for (auto u : adj[n])
if ((!oncyc[g0(u)] || g0(u) == rn) && g0(u) != e)
find_diam(g0(u), n, d + g1(u));
}
main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> N;
for (int i = 1; i <= N; i++) {
link[i] = i;
sz[i] = 1;
}
for (int i = 1; i <= N; i++) {
cin >> U >> L;
adj[i].eb(U, L, i);
adj[U].eb(i, L, i);
unite(i, U);
}
for (int i = 1; i <= N; i++)
if (find(i) == i) comp.pb(i);
for (int i : comp) {
dfs(i);
//cout << "ST " << st << " ED " << ed << " IGN " << ign[i] << '\n';
find_path(st);
}
for (int i = 1; i <= N; i++) {
if (oncyc[i]) {
rn = i;
ed = st = 0;
find_diam(i);
ldpath[i] = ed;
ed = 0;
find_diam(st);
lpath[find(i)] = max(lpath[find(i)], ed);
}
}
for (int i : comp) {
pref[0] = 0;
ll total = le[i];
//for (int j : path[i]) cout << j << ' ';
//cout << '\n';
for (int j = 0; j < wt[i].size(); j++)
pref[j + 1] = pref[j] + wt[i][j], total += wt[i][j];
ll fs = ldpath[path[i][0]] - pref[0], snd = ldpath[path[i][0]] + pref[0];
for (int j = 1; j < path[i].size(); j++) {
int curr = path[i][j];
//cout << "FS " << fs + ldpath[curr] + pref[j] << '\n';
//cout << "SND " << snd + ldpath[curr] - pref[j] + total << '\n';
lpath[i] = max(lpath[i], fs + ldpath[curr] + pref[j]);
lpath[i] = max(lpath[i], snd + ldpath[curr] - pref[j] + total);
fs = max(fs, ldpath[curr] - pref[j]);
snd = max(snd, ldpath[curr] + pref[j]);
}
ans += lpath[i];
}
cout << ans << '\n';
}
Compilation message
islands.cpp:90:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
90 | main() {
| ^
islands.cpp: In function 'int main()':
islands.cpp:127:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
127 | for (int j = 0; j < wt[i].size(); j++)
| ~~^~~~~~~~~~~~~~
islands.cpp:130:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
130 | for (int j = 1; j < path[i].size(); j++) {
| ~~^~~~~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
48 ms |
70892 KB |
Output is correct |
| 2 |
Runtime error |
86 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 3 |
Runtime error |
85 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 4 |
Correct |
48 ms |
70892 KB |
Output is correct |
| 5 |
Runtime error |
84 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 6 |
Correct |
49 ms |
70904 KB |
Output is correct |
| 7 |
Correct |
48 ms |
70892 KB |
Output is correct |
| 8 |
Runtime error |
82 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 9 |
Correct |
49 ms |
71020 KB |
Output is correct |
| 10 |
Correct |
48 ms |
70836 KB |
Output is correct |
| 11 |
Correct |
48 ms |
70892 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
83 ms |
131072 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
83 ms |
131072 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
94 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
127 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
156 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
199 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
358 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
336 ms |
131076 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| 2 |
Halted |
0 ms |
0 KB |
- |
