最近做了好多题都或多或少和并查集带点关系,稍微记录一下

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package 并查集模板;  
  
public class Main {  
    static int[] pre;  
    static int[] sum;  
    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
  
    }  
  
    static int find(int x) {  
        int r = x;  
        while (pre[r] != r)  
            r = pre[r];  
        int i = x, j;  
        while (i != r) {  
            j = pre[i];  
            pre[i] = r;  
            i = j;  
        }  
        return r;  
    }  
  
    static void union(int x, int y){  
        int fx = find(x), fy = find(y);  
        if (fx != fy){  
            pre[fx] = fy;  
            sum[fy]+=sum[fx];  
        }  
              
    }  
}