#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e5 + 10;
int n, tmpp[MAXN], dp[MAXN][4];
int mx1[MAXN], mx2[MAXN], DP[MAXN];
vector< pair< int, int> > adj[MAXN];
int ans;
void dfs(int u, int p = -1){
mx1[u] = mx2[u] = -INT_MAX/2;
for(int i = 0; i < adj[u].size(); i ++){
int v = adj[u][i].first, w = adj[u][i].second;
if( v == p) continue;
dfs(v, u);
dp[v][1] += w;
dp[v][2] = max(dp[v][1], dp[v][0]);
DP[u] += dp[v][2];
dp[u][0] += dp[v][2];
int tmp = dp[v][0] - dp[v][2] + w;
if( tmp > mx1[u]) mx2[u] = mx1[u], mx1[u] = tmp;
else if(tmp > mx2[u]) mx2[u] = tmp;
}
dp[u][1] = -INT_MAX/2;
if( mx1[u] > -INT_MAX/2 )
dp[u][1] = dp[u][0] + mx1[u];
}
void dfs2(int u, int p = -1){
if( tmpp[u] > mx1[u]) mx2[u] = mx1[u], mx1[u] = tmpp[u];
else if(tmpp[u] > mx2[u]) mx2[u] = tmpp[u];
ans = max(ans, DP[u]);
for(int i= 0; i < adj[u].size(); i ++){
int v = adj[u][i].first;
if( v == p) continue;
int w = adj[u][i].second;
int idk = DP[u] - dp[v][2];
int idk2 = dp[v][0] - dp[v][2] + w;
if( idk2 == mx1[u]) idk2 = mx2[u];
else idk2 = mx1[u];
int x = idk;
if( idk2 != -INT_MAX/2)
x = max(x, idk + idk2 + w);
DP[v] += x;
tmpp[v] = idk + w - x;
dfs2(v, u);
}
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n;
for(int i = 1; i < n; i ++){
int a, b, w;
cin >> a >> b >> w, a --, b --;
adj[a].push_back({b, w}), adj[b].push_back({a, w});
}
dfs(0);
tmpp[0] = -INT_MAX/2;
dfs2(0, 0);
cout << ans << endl;
return 0;
}
Compilation message
beads.cpp: In function 'void dfs(int, int)':
beads.cpp:13:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
13 | for(int i = 0; i < adj[u].size(); i ++){
| ~~^~~~~~~~~~~~~~~
beads.cpp: In function 'void dfs2(int, int)':
beads.cpp:35:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
35 | for(int i= 0; i < adj[u].size(); i ++){
| ~~^~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 2 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 3 |
Correct |
5 ms |
5208 KB |
Output is correct |
| 4 |
Correct |
6 ms |
5100 KB |
Output is correct |
| 5 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 6 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 7 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 8 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 9 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 10 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 11 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 12 |
Correct |
4 ms |
5100 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 2 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 3 |
Correct |
5 ms |
5208 KB |
Output is correct |
| 4 |
Correct |
6 ms |
5100 KB |
Output is correct |
| 5 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 6 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 7 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 8 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 9 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 10 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 11 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 12 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 13 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 14 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 15 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 16 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 17 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 18 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 19 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 20 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 21 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 22 |
Correct |
4 ms |
5100 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 2 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 3 |
Correct |
5 ms |
5208 KB |
Output is correct |
| 4 |
Correct |
6 ms |
5100 KB |
Output is correct |
| 5 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 6 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 7 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 8 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 9 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 10 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 11 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 12 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 13 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 14 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 15 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 16 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 17 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 18 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 19 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 20 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 21 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 22 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 23 |
Correct |
7 ms |
5612 KB |
Output is correct |
| 24 |
Correct |
8 ms |
5484 KB |
Output is correct |
| 25 |
Correct |
6 ms |
5484 KB |
Output is correct |
| 26 |
Correct |
9 ms |
5868 KB |
Output is correct |
| 27 |
Correct |
9 ms |
5868 KB |
Output is correct |
| 28 |
Correct |
9 ms |
5996 KB |
Output is correct |
| 29 |
Correct |
8 ms |
5868 KB |
Output is correct |
| 30 |
Correct |
8 ms |
5868 KB |
Output is correct |
| 31 |
Correct |
8 ms |
6252 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 2 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 3 |
Correct |
5 ms |
5208 KB |
Output is correct |
| 4 |
Correct |
6 ms |
5100 KB |
Output is correct |
| 5 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 6 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 7 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 8 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 9 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 10 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 11 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 12 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 13 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 14 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 15 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 16 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 17 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 18 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 19 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 20 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 21 |
Correct |
5 ms |
5100 KB |
Output is correct |
| 22 |
Correct |
4 ms |
5100 KB |
Output is correct |
| 23 |
Correct |
7 ms |
5612 KB |
Output is correct |
| 24 |
Correct |
8 ms |
5484 KB |
Output is correct |
| 25 |
Correct |
6 ms |
5484 KB |
Output is correct |
| 26 |
Correct |
9 ms |
5868 KB |
Output is correct |
| 27 |
Correct |
9 ms |
5868 KB |
Output is correct |
| 28 |
Correct |
9 ms |
5996 KB |
Output is correct |
| 29 |
Correct |
8 ms |
5868 KB |
Output is correct |
| 30 |
Correct |
8 ms |
5868 KB |
Output is correct |
| 31 |
Correct |
8 ms |
6252 KB |
Output is correct |
| 32 |
Correct |
32 ms |
9324 KB |
Output is correct |
| 33 |
Correct |
33 ms |
9324 KB |
Output is correct |
| 34 |
Correct |
34 ms |
9240 KB |
Output is correct |
| 35 |
Correct |
282 ms |
22252 KB |
Output is correct |
| 36 |
Correct |
225 ms |
22380 KB |
Output is correct |
| 37 |
Correct |
223 ms |
22252 KB |
Output is correct |
| 38 |
Correct |
153 ms |
22748 KB |
Output is correct |
| 39 |
Correct |
139 ms |
22736 KB |
Output is correct |
| 40 |
Correct |
150 ms |
22776 KB |
Output is correct |
| 41 |
Correct |
211 ms |
25700 KB |
Output is correct |
