// Online C++ compiler to run C++ program online
#include <bits/stdc++.h>
using namespace std;
struct edge
{
int x,d;
edge(){}
edge(int _x,int _d)
{
x=_x;
d=_d;
}
};
int n;
int a[200001];
vector<edge> v[200001];
void read()
{
cin>>n;
for(int i=1;i<=n;i++)
cin>>a[i];
for(int i=1;i<n;i++)
{
int x,y,z;
cin>>x>>y>>z;
v[x].push_back({y,z});
v[y].push_back({x,z});
}
}
vector<int> e[200001];
int cnt[200001];
void dfs(int i,int curr,int bg,int p)
{
for(int j=0;j<v[i].size();j++)
{
edge nb=v[i][j];
if(nb.x==p)continue;
int d=curr+nb.d;
if(a[bg]-d>a[nb.x])dfs(nb.x,d,bg,i);
else
{
cout<<bg<<" "<<nb.x<<endl;
cnt[nb.x]++,e[bg].push_back(nb.x);
}
}
}
int main() {
read();
for(int i=1;i<=n;i++)
{
dfs(i,0,i,0);
}
int ans=0;
for(int i=1;i<=n;i++)
if(cnt[i]==0)ans++;
cout<<ans<<endl;
return 0;
}
/*
10
1 2 2 2 6 3 4 5 4 3
1 2 5
2 3 1
2 4 5
4 5 2
4 6 4
4 7 3
1 8 1
8 9 5
8 10 4
1 2
1 8
2 1
2 3
2 4
3 2
4 2
4 5
4 6
4 7
5 2
5 6
5 7
6 4
7 4
8 2
8 9
8 10
9 8
10 8
*/
Compilation message
necklace.cpp: In function 'void dfs(int, int, int, int)':
necklace.cpp:37:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<edge>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
37 | for(int j=0;j<v[i].size();j++)
| ~^~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
4 ms |
9816 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
4 ms |
9816 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
4 ms |
9816 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |