nyoj 吝啬的国度 图的遍历

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<string>
 6 #include<queue>
 7 #include<algorithm>
 8 #include<map>
 9 #include<iomanip>
10 #include<climits>
11 #include<string.h>
12 #include<cmath>
13 #include<stdlib.h>
14 #include<vector>
15 #include<stack>
16 #include<set>
17 using namespace std;
18 #define INF 1000000007
19 #define MAXN 4010
20 #define Mod 1000007
21 #define N 100010
22 #define NN 30
23 #define sigma_size 3
24 const int MAX = 1000100;
25 const int maxn = 6e5 + 10;
26 using namespace std;
27 typedef long long LL;
28 
29 int T;
30 int n, s;
31 int u, v;
32 vector<int> G[100010];
33 int flag[100010];
34 
35 void dfs(int u)
36 {
37     for (int i = 0; i < G[u].size(); ++i) {
38         int v = G[u][i];
39         if (!flag[v]) {
40             flag[v] = u;
41             dfs(v);
42         }
43     }
44 }
45 
46 void run()
47 {
48     cin >> n >> s;
49     for (int i = 0; i <= n; ++i) {
50         G[i].clear();
51         flag[i] = 0;
52     }
53     for (int i = 1; i < n; ++i) {
54         scanf("%d%d",&u,&v);
55         G[u].push_back(v);
56         G[v].push_back(u);
57     }
58     flag[s] = -1;
59     dfs(s);
60     printf("%d", flag[1]);
61     for (int i = 2; i <= n; ++i) {
62         printf(" %d", flag[i]);
63     }
64     puts("");
65 }
66 
67 int main()
68 {
69     cin >> T;
70     while (T--)
71         run();
72     //system("pause");
73     return 0;
74 }