HDU 1232 smooth Engineering

This topic is also a typical use of the Minimum Spanning Tree Algorithm. Different from other questions, the other requirement is that the minimum number of edges to be added, so that any two
Points are related. The query set algorithm is used to calculate the number of times the two paths are merged Based on the map given by the question, even if the minimum number of paths to be added is used.

1 # include <stdio. h>
2 # include <stdlib. h>
3
4 int father [1001], tot; // father [I] records the I BOSS!
5 // tot count the minimum number of paths to be added at first!
6
7 int find (int x)
8 {// find the BOSS of x!
9 int r = x;
10 while (r! = Father [r]) r = father [r];
11 return r ;//
12}
13
14 void join (int a, int B)
15 {// unify the BOSS of a and B!
16 int fa = find (a), fb = find (B );
17 if (fa! = Fb)
18 {
19 father [fa] = fb;
20 tot --; // unifies the BOSS of the two camps at a time, so the number of paths to be added is reduced by one!
21}
22}
23
24 int main ()
25 {
26 int n, m, x, y;
27 while (scanf ("% d", & n), n)
28 {
29 scanf ("% d", & m );
30 tot = n-1; // The number of minimum edges required by the initialization tot equals to n points!
31 father [n + 1];
32 for (int I = 1; I <= n; I ++) father [I] = I; // initialize your own BOSS!
33
34 for (int I = 1; I <= m; I ++)
35 {
36 scanf ("% d", & x, & y );
37 join (x, y );
38}
39 printf ("% d \ n", tot); // outputs the number of edges required on an existing basis!
40}
41 return 0;
42}
43