HDU1856More is better(并查集)

最近发现以前的东西都忘得差不多了，在这里刷刷水题

并查集：

 1 int find_parent(int x)
 2 {
 3     return x = p[x] ? x : p[x] = find_parent(p[x]);
 4 }
 5 
 6 void merg(int a,int b)
 7 {
 8     int x = find_parent(a);
 9     int y = find_parent(b);
10     if(x != y)
11     {
12         p[x] = y;
13     }
14 }

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<string.h>
 4 #include<map>
 5 #include<vector>
 6 #include<set>
 7 #include<stack>
 8 #include<queue>
 9 #include<algorithm>
10 #include<stdlib.h>
11 using namespace std;
12 #define MAX(a,b) (a > b ? a : b)
13 #define MIN(a,b) (a < b ? a : b)
14 #define MAXN  10000001
15 #define INF 2000000007
16 #define mem(a) memset(a,0,sizeof(a))
17 
18 int p[MAXN];
19 int ans[MAXN];
20 
21 int find(int x)
22 {
23     return x==p[x]? x : p[x] = find(p[x]);
24 }
25 
26 void merg(int a, int b)
27 {
28     int x = find(a);
29     int y = find(b);
30     if(x != y)
31     {
32         p[x] = y;
33         ans[y] +=ans[x];
34     }
35 }
36 
37 int main()
38 {
39     int n;
40     while(~scanf("%d", &n))
41     {
42         if(n == 0)
43         {
44             printf("1
");
45             continue;
46         }
47         int a,b,i;
48         for(i =0;i<= MAXN;i++)
49         {
50             p[i] = i;
51             ans[i] =1;
52         }
53         for(i = 0; i < n ;i++)
54         {
55             scanf("%d%d",&a, &b);
56             merg(a,b);
57         }
58         int max = 0;
59         for(i =0 ;i<=MAXN;i++)
60         {
61             max = MAX(max, ans[i]);
62         }
63         printf("%d
",max);
64     }
65     return 0;
66 }