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[Leetcode]-Contains Duplicate HashTbale重解

2015-07-07 21:54 447 查看
Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Hide Tags: Array, Hash Table

题目:输入int型数组,检测其中是否有重复的元素,如果有重复的元素则反复true,否则返回false

解法一:暴力求解,两层for循环,1600ms

//暴力求解
bool containsDuplicate(int* nums, int numsSize) {
    int i = 0,j=0;
    for(i=0;i<numsSize;i++)
    {
        for(j=i+1;j<numsSize;j++)
            if(nums[i] == nums[j])
                return true;
    }
    return false;
}


解法二:hashTable解法16ms

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
//hashtable
typedef int ElementType;

//hashtable
typedef unsigned int index1;
typedef struct listnode* position;
typedef struct listnode* list;
struct listnode{
    ElementType data;
    position next;
};

typedef struct hashtbl*  hashtable;
struct hashtbl {
    int tablesize;
    list *thelists;
};

index1 HashFunc(const ElementType key,int tablesize)
{
    //unsigned int hashval = 0;
    //while(*key != '\0')   
        //hashval = (hashval << 5) + *key++;
    //return hashval % tablesize;

    int index = key % tablesize;
    return  index = index >= 0? index: index+tablesize;
}

hashtable InitializeHashTable(int tablesize)
{
    hashtable H;
    H = (hashtable)malloc(sizeof(hashtable));
    if(NULL == H) return NULL;

    H->tablesize = tablesize;

    H->thelists = (list*)malloc(sizeof(list) * H->tablesize);
    int i = 0;
    for(i=0;i<H->tablesize;i++)//有表头
    {
        H->thelists[i] = (list)malloc(sizeof(struct listnode));
        H->thelists[i]->next = NULL;
    }
    return H;
}
void DeleteHashTable(hashtable H)
{
    position P,tem;
    int i = 0;
    for(i=0;i<H->tablesize;i++)
    {
        P = H->thelists[i]->next;
        while(P != NULL)
        {
            tem = P;
            free(tem);
            P=P->next;
        }
    }
    free(H->thelists);
    free(H);
}
position Find(ElementType key,hashtable H)
{
    position P;
    list L;
    L = H->thelists[ HashFunc( key, H->tablesize) ];
    P = L->next;
    while(P != NULL && P->data != key)
        P = P->next;

    return P;
}

bool Insert(ElementType key,hashtable H)
{
    position pos,newnode;
    list L;
    pos = Find(key,H);
    if(pos == NULL)
    {
        newnode = (position)malloc(sizeof(position));
        L = H->thelists[ HashFunc( key, H->tablesize) ];
        newnode->data = key;
        newnode->next = L->next;
        L->next = newnode;
    }
    else
        return true;
}
void PrintHashTable(hashtable H)
{
    position P;
    int i = 0;
    for(i=0;i<H->tablesize;i++)
    {
        P = H->thelists[i]->next;
        printf("H->thelists[%d] = ",i);
        while(P != NULL)
        {
            printf(" %d ->",P->data);
            P=P->next;
        }
        printf("NULL\n");   
    }
}

bool containsDuplicate(int* nums, int numsSize) {
    hashtable H;
    int tablesize  = numsSize * 2;
    H = InitializeHashTable(tablesize);
    int i = 0;
    for(i=0; i< numsSize; i++){
        position pos,newnode;
        list L;
        pos = Find(nums[i],H);
        if(pos == NULL)
        {
            newnode = (position)malloc(sizeof(position));
            L = H->thelists[ HashFunc( nums[i], H->tablesize) ];
            newnode->data = nums[i];
            newnode->next = L->next;
            L->next = newnode;
        }
        else
            return true;
    }
    return false;
}

int main()
{
    int nums[5] = {1,0,34,56,57};
    bool r = containsDuplicate(nums,5);
    printf("containsDuplicate is : %d \n",r);
}
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