POJ1655 Balancing Art

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5  
 6 inline void read(int &x)
 7 {
 8     x = 0;char ch = getchar();char c = ch;
 9     while(ch > ‘9‘ || ch < ‘0‘)c = ch, ch = getchar();
10     while(ch <= ‘9‘ && ch >= ‘0‘)x = x * 10 + ch - ‘0‘, ch = getchar();
11     if(c == ‘-‘)x = -x;
12 }
13 inline int max(int a, int b){return a > b ? a : b;}
14 inline int min(int a, int b){return a < b ? a : b;}
15 
16 const int INF = 0x3f3f3f3f;
17 const int MAXN = 200000 + 10;
18 
19 struct Edge
20 {
21     int u,v,next;
22 }edge[MAXN << 1];
23 int t,n,head[MAXN],cnt,b[MAXN],dp[MAXN],ma,g;
24 inline void insert(int a, int b){edge[++cnt] = Edge{a,b,head[a]};head[a] = cnt;}
25 
26 void dfs(int u)
27 {
28     int pos, tmp = -1;
29     dp[u] = 1;
30     for(pos = head[u];pos;pos = edge[pos].next)
31     {
32         int v = edge[pos].v;
33         if(!b[v])
34         {
35             b[v] = true;
36             dfs(v);
37             dp[u] += dp[v];
38             tmp = max(tmp, dp[v]);
39         }
40     }
41     tmp = max(tmp, n - dp[u]);
42     if(tmp < ma)
43         ma = tmp,g = u;
44     if(tmp == ma)
45         g = min(g, u);
46 }
47 
48 int main()
49 {
50     read(t);
51     register int i,tmp1,tmp2;
52     for(;t;--t)
53     {
54         ma = INF,g = INF;
55         memset(edge, 0, sizeof(edge));
56         memset(head, 0, sizeof(head));
57         cnt = 0;memset(dp, 0, sizeof(dp));
58         memset(b, 0, sizeof(b));
59         read(n);
60         for(i = 1;i < n;++ i)
61         {
62             read(tmp1);read(tmp2);
63             insert(tmp1, tmp2);insert(tmp2, tmp1);
64         }
65         b[1] = true;
66         dfs(1);
67         printf("%d %d\n", g, ma);
68     }
69     return 0;
70 }