#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define w (a[e][1])
#define V() (e == u ? a[e][0] : e)
#define v V()
#define E u
const int LIM = 1e6;
vector<int> g[LIM];
array<int, 2> a[LIM];
int r, p[LIM];
ll d[LIM], s[LIM], best;
bitset<LIM> vis;
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
for(int i=0; i<n; ++i){
cin >> a[i][0] >> a[i][1]; --a[i][0];
g[a[i][0]].push_back(i);
}
fill(p, p+n, -1);
ll ans = 0;
stack<int> st;
for(int z=0; z<n; ++z){
if(vis[z]) continue;
r = -1, best = 0;
st.push(z);
while(!st.empty()){
int u = st.top();
if(!vis[u]){
vis[u] = 1;
for(int e : g[u]) if(e != p[u]){
if(vis[v]){
r = e + (vis[u] = 0);
break;
}else{
p[v] = e;
st.push(v);
}
if(r >= 0) break;
}
if(u != p[u]){
if(vis[a[u][0]]) r = u + (vis[u] = 0);
p[a[u][0]] = u;
st.push(a[u][0]);
}
}else{
vis[u] = 0;
st.pop();
}
if(r >= 0) while(!st.empty()) vis[st.top()] = 0, st.pop();
}
st.push(r);
while(!st.empty()){
int u = st.top();
if(!vis[u]){
vis[u] = 1, s[u] = d[u];
for(int e : g[u]) if(e != r && !vis[v]){
p[v] = u;
d[v] = d[u] + (ll)w;
st.push(v);
}
if(u != r && !vis[a[u][0]]){
p[a[u][0]] = u;
d[a[u][0]] = d[u] + (ll)a[u][1];
st.push(a[u][0]);
}
}else{
ll curr = 0;
for(int e : g[u]) if(e != r){
s[u] = max(s[u], s[v]);
best = max(best, curr + s[v] - d[u]);
curr = max(curr, s[v] - d[u]);
}
if(u != r){
s[u] = max(s[u], s[a[u][0]]);
best = max(best, curr + s[a[u][0]] - d[u]);
curr = max(curr, s[a[u][0]] - d[u]);
}
st.pop();
}
}
int u = a[r][0], last = -1;
while(1){
vis[u] = 0;
s[u] = d[u];
for(int e : g[u])
if(e != r && v != p[u] && v != last) s[u] = max(s[u], s[v]);
if(u != r && a[u][0] != p[u] && a[u][0] != last) s[u] = max(s[u], s[a[u][0]]);
if(u == r) break;
last = u;
u = p[u];
}
u = r;
while(1){
vis[u] = 1;
for(int e : g[u])
if(e != r && v != p[u] && !vis[v]) last = v;
if(u != r && a[u][0] != p[u] && !vis[a[u][0]]) last = a[u][0];
s[last] = max(s[last], s[u]);
if(u == a[r][0]) break;
u = last;
last = -1;
}
u = a[r][0], last = -1;
ll res = 0;
while(u != r){
ll mx = 0;
for(int e : g[u])
if(e != r && v != p[u] && v != last) mx = max(mx, s[v] - d[u]);
if(a[u][0] != p[u] && a[u][0] != last) mx = max(mx, s[a[u][0]] - d[u]);
res = max(res, d[a[r][0]] - d[u] + mx + s[p[u]]);
last = u;
u = p[u];
}
res += a[r][1];
ans += max(best, res);
}
cout << ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
16 ms |
23716 KB |
Output is correct |
2 |
Correct |
18 ms |
23824 KB |
Output is correct |
3 |
Correct |
17 ms |
23856 KB |
Output is correct |
4 |
Correct |
16 ms |
23728 KB |
Output is correct |
5 |
Correct |
16 ms |
23756 KB |
Output is correct |
6 |
Correct |
16 ms |
23768 KB |
Output is correct |
7 |
Correct |
16 ms |
23756 KB |
Output is correct |
8 |
Correct |
16 ms |
23756 KB |
Output is correct |
9 |
Correct |
17 ms |
23740 KB |
Output is correct |
10 |
Correct |
17 ms |
23756 KB |
Output is correct |
11 |
Correct |
17 ms |
23756 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
23756 KB |
Output is correct |
2 |
Correct |
17 ms |
23876 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
18 ms |
23884 KB |
Output is correct |
2 |
Correct |
19 ms |
23996 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
22 ms |
24556 KB |
Output is correct |
2 |
Correct |
40 ms |
25372 KB |
Output is correct |
3 |
Correct |
24 ms |
24800 KB |
Output is correct |
4 |
Correct |
22 ms |
24324 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
36 ms |
26092 KB |
Output is correct |
2 |
Correct |
53 ms |
28760 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
94 ms |
33068 KB |
Output is correct |
2 |
Correct |
109 ms |
37220 KB |
Output is correct |
3 |
Correct |
126 ms |
36412 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
151 ms |
43448 KB |
Output is correct |
2 |
Correct |
219 ms |
47124 KB |
Output is correct |
3 |
Correct |
227 ms |
59732 KB |
Output is correct |
4 |
Correct |
259 ms |
56132 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
311 ms |
59312 KB |
Output is correct |
2 |
Correct |
1056 ms |
76264 KB |
Output is correct |
3 |
Correct |
313 ms |
60728 KB |
Output is correct |
4 |
Correct |
362 ms |
71160 KB |
Output is correct |
5 |
Correct |
463 ms |
68920 KB |
Output is correct |
6 |
Correct |
904 ms |
69404 KB |
Output is correct |
7 |
Correct |
421 ms |
76192 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
422 ms |
86688 KB |
Output is correct |
2 |
Correct |
421 ms |
100108 KB |
Output is correct |
3 |
Correct |
442 ms |
102164 KB |
Output is correct |
4 |
Correct |
419 ms |
93616 KB |
Output is correct |
5 |
Correct |
448 ms |
83260 KB |
Output is correct |
6 |
Correct |
358 ms |
86300 KB |
Output is correct |
7 |
Correct |
945 ms |
85132 KB |
Output is correct |