/**
* author: Haunted_Cpp
**/
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
template<typename T> ostream &operator << (ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream &operator << (ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream &operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
#ifdef LOCAL
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#else
#define debug(...) 47
#endif
typedef long long i64;
const int MAX_N = 1e6 + 5;
vector<vector<int>> g(MAX_N);
int Time = 0, cycle_start, cycle_end;
vector<int> nxt(MAX_N), cost(MAX_N), par(MAX_N), cycle;
vector<short> color(MAX_N);
bitset<MAX_N> is_cycle;
void find_cycle(int node, int p) {
color[node] = 1;
for (auto et : g[node]) {
if (et == p && !(nxt[p] == node && nxt[node] == p)) continue;
if (color[et] == 0) {
par[et] = node;
find_cycle(et, node);
} else if (color[et] == 1) {
cycle_start = et;
cycle_end = node;
}
}
color[node] = 2;
}
int root;
pair<i64, int> dfs(int node, int p) {
pair<i64, int> best_way = {0, node};
for (auto et : g[node]) {
const int w = (nxt[node] == et ? cost[node] : cost[et]);
if (et != root && is_cycle[et]) continue;
if (et != p) {
pair<i64, int> cur = dfs(et, node);
cur.first += w;
best_way = max(best_way, cur);
}
}
return best_way;
}
i64 get_depth(int node, int p) {
i64 mx = 0;
for (auto et : g[node]) {
const int w = (nxt[node] == et ? cost[node] : cost[et]);
if (is_cycle[et]) continue;
if (et != p) {
mx = max(mx, w + get_depth(et, node));
}
}
return mx;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
for (int st = 0; st < n; st++) {
int et, w;
cin >> et >> w;
--et;
nxt[st] = et;
cost[st] = w;
g[st].emplace_back(et);
g[et].emplace_back(st);
}
i64 ans = 0;
for (int i = 0; i < n; i++) {
if (color[i] != 0) continue;
cycle.clear();
find_cycle(i, -1);
i64 cycle_cost = 0;
for (int cur = cycle_end; cur != cycle_start; cur = par[cur]) {
cycle.emplace_back(cur);
is_cycle[cur] = 1;
}
is_cycle[cycle_start] = 1;
cycle.emplace_back(cycle_start);
reverse(cycle.begin(), cycle.end());
for (int j = 1; j < (int) cycle.size(); j++) {
const int st = cycle[j - 1];
const int et = cycle[j];
const int w = (nxt[st] == et ? cost[st] : cost[et]);
cycle_cost += w;
}
cycle_cost += (nxt[cycle.back()] == cycle[0] ? cost[cycle.back()] : cost[cycle[0]]);
i64 res = 0;
for (auto to : cycle) {
root = to;
pair<i64, int> best_way = dfs(root, -1);
res = max(res, dfs(best_way.second, -1).first);
}
i64 ccw = get_depth(cycle[0], -1);
i64 cw = get_depth(cycle[0], -1);
i64 start = 0;
for (int j = 1; j < (int) cycle.size(); j++) {
const int st = cycle[j - 1];
const int et = cycle[j];
const int w = (nxt[st] == et ? cost[st] : cost[et]);
start += w;
res = max(res, cw + start + get_depth(et, -1));
cw = max(cw, -start + get_depth(et, -1));
const i64 other = cycle_cost - start;
res = max(res, ccw + other + get_depth(et, -1));
ccw = max(ccw, start + get_depth(et, -1));
}
res = max({res, cw, ccw});
ans += res;
}
cout << ans << '\n';
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
27 ms |
37496 KB |
Output is correct |
| 2 |
Correct |
27 ms |
37504 KB |
Output is correct |
| 3 |
Correct |
27 ms |
37632 KB |
Output is correct |
| 4 |
Correct |
26 ms |
37504 KB |
Output is correct |
| 5 |
Correct |
27 ms |
37496 KB |
Output is correct |
| 6 |
Correct |
28 ms |
37496 KB |
Output is correct |
| 7 |
Correct |
27 ms |
37504 KB |
Output is correct |
| 8 |
Correct |
27 ms |
37504 KB |
Output is correct |
| 9 |
Correct |
27 ms |
37504 KB |
Output is correct |
| 10 |
Correct |
28 ms |
37520 KB |
Output is correct |
| 11 |
Correct |
27 ms |
37504 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
29 ms |
37632 KB |
Output is correct |
| 2 |
Correct |
27 ms |
37632 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
29 ms |
37632 KB |
Output is correct |
| 2 |
Correct |
32 ms |
37888 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
35 ms |
38144 KB |
Output is correct |
| 2 |
Correct |
47 ms |
39928 KB |
Output is correct |
| 3 |
Correct |
40 ms |
38272 KB |
Output is correct |
| 4 |
Correct |
38 ms |
37884 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
52 ms |
40824 KB |
Output is correct |
| 2 |
Correct |
66 ms |
42340 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
123 ms |
45816 KB |
Output is correct |
| 2 |
Correct |
127 ms |
51116 KB |
Output is correct |
| 3 |
Correct |
147 ms |
58312 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
177 ms |
51576 KB |
Output is correct |
| 2 |
Correct |
245 ms |
70132 KB |
Output is correct |
| 3 |
Correct |
258 ms |
78084 KB |
Output is correct |
| 4 |
Correct |
322 ms |
90220 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
369 ms |
72800 KB |
Output is correct |
| 2 |
Correct |
1073 ms |
110928 KB |
Output is correct |
| 3 |
Correct |
346 ms |
64384 KB |
Output is correct |
| 4 |
Correct |
446 ms |
94956 KB |
Output is correct |
| 5 |
Correct |
450 ms |
94832 KB |
Output is correct |
| 6 |
Correct |
1621 ms |
68512 KB |
Output is correct |
| 7 |
Correct |
467 ms |
119464 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
411 ms |
131076 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
