冲突解决策略是定义一个序列F(i)=ri，其中r0=0且r1,r2……rN是前N个整数的随机排列（每个整数恰好出现一次）

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数据结构与算法分析——c语言描述练习5.5e 答案

hashQuad.c

#include"hashQuad.h"#include"fatal.h"#include<math.h>#include<string.h>#define MinTableSize 5enum KindOfEntry { Legitimate, Empty, Deleted };struct HashEntry {ElementType element;enum KindOfEntry info;};typedef struct HashEntry Cell;struct HashTbl {int tableSize;int hasInsertedNum;Cell *theCells;//数组int* randomArr;};static int RandInt(int i, int j) {int temp;temp = (int)(i + (1.0*rand() / RAND_MAX)*(j - i));return temp;}static 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;}}static int hash(ElementType key, int tableSize) {return key % (tableSize);}static int isPrime(int num) {for (int i = 2; i <= sqrt(num); i++)if (num%i == 0)return 0;return 1;}static int nextPrime(int num) {int i = num;while (!isPrime(i))i++;return i;}int isLegitimate(Position pos, HashTable h) {return h->theCells[pos].info == Legitimate;}HashTable initializeTable(int tableSize) {HashTable h;int i;if (tableSize < MinTableSize) {Error("Table size too small");return NULL;}h = malloc(sizeof(struct HashTbl));if (h == NULL)FatalError("Out of space!!!");h->tableSize = nextPrime(tableSize);h->theCells = malloc(sizeof(Cell)*h->tableSize);h->hasInsertedNum = 0;h->randomArr = malloc(sizeof(int)*h->tableSize);getRandomInt(h->randomArr, h->tableSize);if (h->theCells == NULL)FatalError("Out of space!!!");for (i = 0; i < h->tableSize; i++) {h->theCells[i].info = Empty;}return h;}void destroyTable(HashTable h) {free(h->randomArr);free(h->theCells);free(h);}Position find(ElementType key, HashTable h) {Position currentPos = hash(key, h->tableSize);int collisionNum = 0;while (h->theCells[currentPos].info != Empty && h->theCells[currentPos].element != key) {currentPos = (currentPos + h->randomArr[collisionNum++]) % h->tableSize;}return currentPos;}HashTable insert(ElementType key, HashTable h) {if ((double)h->hasInsertedNum / h->tableSize > 0.5)h = rehash(h);Position pos = find(key, h);if (h->theCells[pos].info != Legitimate) {h->theCells[pos].element = key;h->theCells[pos].info = Legitimate;h->hasInsertedNum++;}return h;}HashTable rehash(HashTable h) {HashTable newH = initializeTable(h->tableSize * 2);for (int i = 0; i < h->tableSize; i++)if (h->theCells[i].info == Legitimate)insert(h->theCells[i].element, newH);destroyTable(h);return newH;}ElementType retrive(Position p, HashTable h) {return h->theCells[p].element;}

main.c

#include<stdlib.h>#include"hashQuad.h"#include<stdio.h>#define N 111int randIntArr[N];//这么大的数组放在全局变量上，如果放在main里就是放在程序的堆上，运行时再分配。放在外面就是编译时就分配在静态数据那。int main() {for (int i = 0; i < N; i++)randIntArr[i] = rand();HashTable h = initializeTable(100);for (int i = 0; i < N; i++)h = insert(randIntArr[i], h);destroyTable(h);}

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