https://www.luogu.org/problemnew/show/P1111
1 #include<iostream> 2 #include<cstdio> 3 #include<cmath> 4 #include<algorithm> 5 using namespace std; 6 typedef long long ll; 7 int fa[100010]; 8 int n, m; 9 int find(int x) 10 { 11 return x == fa[x] ? fa[x] : fa[x] = find(fa[x]); 12 } 13 void baba(int x, int y) 14 { 15 int fx = find(x); 16 int fy = find(y); 17 fa[fx] = fy; 18 } 19 struct node { 20 int from; 21 int to; 22 int jz; 23 }road[100010]; 24 bool cmp(node a, node b) 25 { 26 return a.jz < b.jz; 27 } 28 bool same(int x, int y) 29 { 30 return find(x) == find(y); 31 } 32 int main() 33 { 34 cin >> n >> m; 35 for (int i = 1; i <= m; i++) 36 { 37 cin >> road[i].from >> road[i].to >> road[i].jz; 38 } 39 for (int i = 1; i <= m; i++) 40 { 41 fa[i] = i; 42 } 43 sort(road + 1, road + m + 1, cmp); 44 int t = 0; 45 int ans = 0; 46 for (int i = 1; i <= m; i++) 47 { 48 if (!same(road[i].from, road[i].to)) 49 { 50 baba(road[i].from, road[i].to); 51 ans++; 52 } 53 if (ans == n - 1) 54 { 55 t = road[i].jz; 56 break; 57 } 58 } 59 if (t == 0) 60 { 61 printf("-1 "); 62 } 63 else 64 { 65 printf("%d ", t); 66 } 67 return 0; 68 }
不要忘记fa数组的初始化