离散集合操作

#include<stdio.h>
#include<stdlib.h>

struct node{
	node* p;
	int rank;
	int x;
};

node* find(node* xp) {
	node* wp, * yp = xp, * zp = xp;
	while (yp->p != NULL) {
		yp = yp->p;
	}
	while (zp->p != NULL) {
		wp = zp->p;
		zp->p = yp;
		zp = wp;
	}
	return yp;
}

node* uni(node* xp, node* yp) {
	node* up, * vp;
	up = find(xp);
	vp = find(yp);
	if (up->rank <= vp->rank) {
		up->p = vp;
		if (up->rank == vp->rank)
			vp->rank++;
		up = vp;
	}
	else
		vp->p = up;
	return up;
}

int main() {
	node x[4]; 
	node y[4];
	for (int i = 0; i < 4; i++) {
		x[i].p=y[i].p=NULL;
		x[i].x = i;
		y[i].x = i + 4;
	}
	x[2].p = x[1].p = &(x[3]); 
	y[2].p = y[1].p = &(y[3]); 
	x[0].p = &(x[2]); 
	y[0].p = &(y[2]);
	x[3].rank = 0, x[2].rank = x[1].rank = 1; 
	y[3].rank = 0, y[2].rank = y[1].rank = 1;
	x[0].rank = 2; 
	y[0].rank = 2;
	node* a = &(x[0]); 
	node* b = &(y[0]);
	node* c = uni(a, b);
	printf("%d", c->x);
	return 0;
}
//输出结果为y[3]=7