算法（Algorithms）第4版 练习 1.5.1

0 1 2 3 4 5 6 7 8 9 
10 components
9 0
0 1 2 3 4 5 6 7 8 0 
9 components
3 4
0 1 2 4 4 5 6 7 8 0 
8 components
5 8
0 1 2 4 4 8 6 7 8 0 
7 components
7 2
0 1 2 4 4 8 6 2 8 0 
6 components
2 1
0 1 1 4 4 8 6 1 8 0 
5 components
5 7
0 1 1 4 4 1 6 1 1 0 
4 components
0 3
4 1 1 4 4 1 6 1 1 4 
3 components
4 2
1 1 1 1 1 1 6 1 1 1 
2 components

    public static void main(String[] args) {
        
        //initialize N components
        int N = StdIn.readInt();
        UFQuickFind uf = new UFQuickFind(N);
        StdOut.println(uf);
        
        while(!StdIn.isEmpty()) {
            
            int p = StdIn.readInt();
            int q = StdIn.readInt();
            
            if(uf.connected(p, q)) {//ignore if connected
                StdOut.println(p + " " + q + " is connected");
                continue;
            }
            
            uf.union(p, q);//connect p and q
            StdOut.println(p + " " + q);
            StdOut.println(uf);
        }