【原创】poj ----- 1611 The Suspects 解题报告

#include <stdio.h>

int man[30001];
int num[30001]; // 记录有几个子节点，但只有根记录的数据才算数

void init(int n)
{
  for (int i = 0; i < n; i ++) {
    man[i] = -1;
    num[i] = 0;
  }
}

int find_root(int child)
{
  if (man[child] == -1)
    return child;
  return man[child] = find_root(man[child]);
}

void union_set(int one, int two) 
{
  int fat1 = find_root(one);
  int fat2 = find_root(two);
  //printf("%d and %d has been union. ", fat1, fat2);
  if (fat1 == fat2)
    return;
  num[fat1] += num[fat2] + 1;
  man[fat2] = fat1;
  //printf("father is %d\n", fat1);
}

int main(void)
{
  int m,n;
  while (scanf("%d%d", &n, &m)) {
    if (m == 0 && n == 0)
      break;
    init(n);
    for (int i = 0; i < m; i ++) {
      int count,pre,now;
      scanf("%d", &count);
      pre = -1;
      for (int j = 0; j < count; j ++) {
    scanf("%d", &now);
    if (pre != -1) {
      union_set(pre, now);
    }
    pre = now;
      }
    }
    int fa = find_root(0);
    
    printf("%d\n", num[fa] + 1);
  }
  return 0;
}