左式堆

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数据结构与算法分析——c语言描述第六章

代码不难。反倒是理解merge挺难的。

一个左式堆，它的子树也是左式堆。合并就是不断递归，直到找到一个空指针，然后合并。并且判断左边的npl是不是大于等于右边的npl。在一层一层返回。所以合并的又是一个左式堆。

leftheap.h

#ifndef _LeftHeap_H#define _LeftHeap_Htypedef int ElementType;struct TreeNode;typedef struct TreeNode *PriorityQueue;PriorityQueue initialize(void);ElementType findMin(PriorityQueue h);int isEmpty(PriorityQueue h);PriorityQueue merge(PriorityQueue h1, PriorityQueue h2);#define insert(X,H) (H=insert1((X),H))PriorityQueue insert1(ElementType X, PriorityQueue h);PriorityQueue deleteMin1(PriorityQueue h);#define deleteMin(H) (H=deleteMin1(H))#endif // !_BinHeap_H

leftheap.c

#include"leftheap.h"#include"fatal.h"struct TreeNode {ElementType element;PriorityQueue left;PriorityQueue right;int np1;};PriorityQueue initialize(void) {return NULL;}ElementType findMin(PriorityQueue h) {if (isEmpty(h))Error("EMPTY HEAP");return h->element;}int isEmpty(PriorityQueue h) {return h == NULL;}static PriorityQueue merge1(PriorityQueue h1, PriorityQueue h2) {if (h1->left == NULL) {h1->left = h2;return h1;}else {h1->right= merge(h1->right, h2);if (h1->right->np1 > h1->left->np1) {PriorityQueue temp;temp = h1->right;h1->right = h1->left;h1->left = temp;}h1->np1 = h1->right->np1 + 1;return h1;}}PriorityQueue merge(PriorityQueue h1, PriorityQueue h2) {if (h1 == NULL)return h2;else if (h2 == NULL)return h1;else {if (h1->element < h2->element)return merge1(h1, h2);elsereturn merge1(h2, h1);}}PriorityQueue insert1(ElementType X, PriorityQueue h) {PriorityQueue newNode = malloc(sizeof(struct TreeNode));newNode->element = X;newNode->left = NULL;newNode->right = NULL;newNode->np1 = 0;return merge(newNode, h);}PriorityQueue deleteMin1(PriorityQueue h) {PriorityQueue temp1 = h->left;PriorityQueue temp2 = h->right;free(h);return merge(temp1, temp2);}

main.c

#include"leftheap.h"#include<stdlib.h>#include<stdio.h>int RandInt(int i, int j) {int temp;temp = (int)(i + (1.0*rand() / RAND_MAX)*(j - i));return temp;}void getRandomInt(int *A, int n) {for (int i = 0; i < n; i++) {A[i] = i + 1;}for (int i = 1; i < n; i++) {//std::swap(A[i], A[RandInt(0, i)]);  int randAdrr = RandInt(0, i);int t = A[i];A[i] = A[randAdrr];A[randAdrr] = t;}}int a[99999999];int main() {int n;scanf("%d", &n);//int *a = malloc(sizeof(int)*n);//if (a == NULL)//fprintf(stderr,"out of memory");getRandomInt(a, n);PriorityQueue h1 = initialize();PriorityQueue h2 = initialize();int i;for (i = 0; i < n / 2; i++)insert(a[i], h1);for (; i < n; i++)insert(a[i], h2);PriorityQueue h = merge(h1, h2);for (int i = 0; i < n; i++) {printf("%d ", findMin(h));deleteMin(h);}//destroy(h);//free(a);}

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