poj 1611
并查集的入门题吧，了解了简单的思想~~~
1 #include <iostream> 2 #include <string> 3 #include <vector> 4 #include <cstdlib> 5 #include <cmath> 6 #include <map> 7 #include <algorithm> 8 #include <list> 9 #include <ctime> 10 #include <set> 11 #include <string.h> 12 #include <queue> 13 #include <cstdio> 14 #define CLR(arr, what) memset(arr, what, sizeof(arr)) 15 typedef long long ll; 16 const int MAX = 100000; 17 using namespace std; 18 19 20 int n, m, i, j; 21 int father[30005], num[30005]; 22 23 void makeSet(int n) 24 { 25 for(i = 0; i < n; i++) 26 { 27 father[i] = i; //使用本身做根 28 num[i] = 1; 29 } 30 } 31 int findSet(int x) 32 { 33 if(father[x] != x) //合并后的树的根是不变的 34 { 35 father[x] = findSet(father[x]); 36 } 37 return father[x]; 38 } 39 40 void Union(int a, int b) 41 { 42 int x = findSet(a); 43 int y = findSet(b); 44 if(x == y) 45 { 46 return; 47 } 48 if(num[x] <= num[y]) 49 { 50 father[x] = y; 51 num[y] += num[x]; 52 } 53 else 54 { 55 father[y] = x; 56 num[x] += num[y]; 57 } 58 } 59 60 int main() 61 { 62 while(scanf("%d %d", &n, &m)!=EOF && n != 0) 63 { 64 makeSet(n); 65 for(i = 0; i < m; i++) 66 { 67 int count, first, b; 68 scanf("%d %d",&count, &first); 69 for(j = 1; j < count; j++) 70 { 71 scanf("%d",&b); 72 Union(first,b); 73 } 74 } 75 printf("%d\n",num[findSet(0)]); 76 } 77 return 0; 78 }
