[Link] https://www.acmicpc.net/problem/1240
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
#include <algorithm>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
// #include <bits/stdc++.h>
using namespace std;
#define for0(i, n) for(int i = 0; i < n; i++)
#define for1(i, n) for(int i = 1; i < n; i++)
#define fori(s, e) for(int i = s; i < e; i++)
#define endl "\n"
typedef long long ll;
const int INF = 987654321;
const int MAX = 100;
int n, m, ans = 0;
vector<vector<pair<int, int>>> edges;
vector<int> parent;
void dfs(int cur, int des, int dis) {
if(cur == des) {
ans = dis;
return;
}
for(pair<int, int> p : edges[cur]) {
if(parent[cur] == p.first) continue;
parent[p.first] = cur;
dfs(p.first, des, dis + p.second);
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m;
for0(i, n) edges.push_back(vector<pair<int, int>>(0, make_pair(0, 0)));
parent.resize(n);
fill(parent.begin(), parent.end(), -1);
for0(i, n-1) {
int a, b, dis; cin >> a >> b >> dis;
a--, b--;
edges[a].push_back(make_pair(b, dis));
edges[b].push_back(make_pair(a, dis));
}
for0(i, m) {
int a, b; cin >> a >> b;
a--, b--;
ans = 0;
fill(parent.begin(), parent.end(), -1);
dfs(a, b, 0);
cout << ans << endl;
}
return 0;
}