LA 3644 X-Plosives

最简单的并查集

多做做水题，加深一下理解

 

 1 //#define LOCAL

 2 #include <cstdio>

 3 

 4 const int maxn = 100000 + 10;

 5 int parent[maxn];

 6 

 7 int GetParent(int a) { return parent[a] == a ? a : parent[a] = GetParent(parent[a]); }

 8 

 9 int main(void)

10 {

11     #ifdef LOCAL

12         freopen("3644in.txt", "r", stdin);

13     #endif

14 

15     int x, y;

16     while(scanf("%d", &x) == 1)

17     {

18         for(int i = 0; i < maxn; ++i)    parent[i] = i;

19         int cnt = 0;

20         while(~x)

21         {

22             scanf("%d", &y);

23             x = GetParent(x); y = GetParent(y);

24             if(x == y)    ++cnt;

25             else        parent[x] = y;

26             scanf("%d", &x);

27         }

28         printf("%d\n", cnt);

29     }

30     return 0;

31 }

代码君