本文主要是介绍红黑树,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#define NIL (&__NIL)
typedef struct Node {
struct Node *lchild, *rchild;
int color, val;
} Node;
Node __NIL;
__attribute__((constructor))
void init_NIL() {
NIL->lchild = NIL->rchild = NIL;
NIL->color = 1, NIL->val = -1;
return ;
}
Node *getNewNode(int a) {
Node *p = (Node *)malloc(sizeof(Node));
p->color = 0, p->val = a;
p->lchild = p->rchild = NIL;
return p;
}
void clear(Node *p) {
if (p == NIL) return ;
clear(p->lchild);
clear(p->rchild);
free(p);
return ;
}
int has_red_child(Node *root) {
return !root->lchild->color || !root->rchild->color;
}
Node *left_rotate(Node *root) {
printf("left%d\n", root->val);
Node *temp = root->rchild;
root->rchild = temp->lchild;
temp->lchild = root;
return temp;
}
Node *right_rotate(Node *root) {
printf("right%d\n", root->val);
Node *temp = root->lchild;
root->lchild = temp->rchild;
temp->rchild = root;
return temp;
}
Node *erase_maintain(Node *root) {
if (root->lchild->color != 2 && root->rchild->color != 2) return root;
if (has_red_child(root)) {
root->color = 0;
root->lchild->color && (root = left_rotate(root), root->color = 1, root->lchild = erase_maintain(root->lchild)) ||
(root = right_rotate(root), root->color = 1, root->rchild = erase_maintain(root->rchild));
return root;
} else {
if((root->lchild->color == 2 && !has_red_child(root->rchild)) ||
(root->rchild->color == 2 && !has_red_child(root->lchild)))
root->color++, root->lchild->color--, root->rchild->color--;
else {
if (root->lchild->color == 2) {
root->lchild->color = 1;
root->rchild->lchild->color || (root->rchild->color = 0, root->rchild = right_rotate(root->rchild), root->rchild->color = 1);
root->rchild->color = root->color;
root = left_rotate(root);
root->lchild->color = root->rchild->color = 1;
} else {
root->rchild->color = 1;
root->lchild->rchild->color || (root->lchild->color = 0, root->lchild = left_rotate(root->lchild), root->lchild->color = 1);
root->lchild->color = root->color;
root = right_rotate(root);
root->rchild->color = root->lchild->color = 1;
}
}
}
return root;
}
Node *predecessor(Node *root) {
root = root->lchild;
while (root->rchild != NIL) root = root->rchild;
return root;
}
Node *__erase(Node *root, int key) {
if (root == NIL) return NIL;
root->val > key && (root->lchild = __erase(root->lchild, key));
root->val < key && (root->rchild = __erase(root->rchild, key));
if (root->val == key) {
if (root->rchild == NIL || root->lchild == NIL) {
Node *temp = root->rchild == NIL ? root->lchild : root->rchild;
temp->color += root->color;
free(root);
return (temp);
}
Node *temp = predecessor(root);
root->val = temp->val;
root->lchild = __erase(root->lchild, root->val);
}
return erase_maintain(root);
}
Node *erase(Node *root, int key) {
if (root == NIL) return root;
printf("\nerase: %d\n", key);
root = __erase(root, key);
root->color = 1;
return root;
}
Node *insert_maintain(Node *root) {
if (root == NIL || !has_red_child(root)) return root;
int a;
if (root->lchild->color == 0 && root->rchild->color == 0) {
if (!has_red_child(root->lchild) && !has_red_child(root->rchild)) return root;
if (has_red_child(root->lchild) || has_red_child(root->rchild)) {
root->lchild->color = root->rchild->color = 1;
root->color = 0;
}
return root;
}
if (!root->lchild->color) {
if (!has_red_child(root->lchild)) return root;
!root->lchild->rchild->color && (root->lchild = left_rotate(root->lchild));
root = right_rotate(root);
}
if (!root->rchild->color) {
if (!has_red_child(root->rchild)) return root;
!root->rchild->lchild->color && (root->rchild = right_rotate(root->rchild));
root = left_rotate(root);
}
root->color = 0, root->lchild->color = root->rchild->color = 1;
return root;
}
Node *__insert(Node *root, int a) {
if (root == NIL) return getNewNode(a);
if (root->val == a) return root;
root->val < a && (root->rchild = __insert(root->rchild, a));
a < root->val && (root->lchild = __insert(root->lchild, a));
return insert_maintain(root);
}
Node *insert(Node *root, int a) {
printf("insert: %d\n");
if (!root) return getNewNode(a);
root = __insert(root, a);
root->color = 1;
return root;
}
void output(Node *root) {
if (root == NIL) return ;
printf("%d, color = %d | (%d, %d)\n", root->val, root->color, root->lchild->val, root->rchild->val);
output(root->lchild);
output(root->rchild);
return ;
}
int main() {
int a;
srand(time(0));
scanf("%d", &a);
Node *root;
for (int i = 0; i < a; i++) root = insert(root, rand() % 100);
output(root);
while (~scanf("%d", &a)) root = erase(root, a), output(root);
return 0;
}
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