查找与排序实验

一、实验目的

1、掌握折半查找方法。

2、掌握快速排序方法。

二、实验内容

1、输入 n 个关键字，完成快速排序。

2、输入两个关键字采用折半查找。

---

#include <stdio.h>
#include <stdlib.h>
int Partition(int *p, int low, int high)
{
    p[0] = p[low];
    int pivotkey = p[low];
    while(low < high)
    {
        while(low < high && p[high] >= pivotkey)
            --high;
        p[low] = p[high];
        while(low < high && p[low] <= pivotkey)
            ++low;
        p[high] = p[low];
    }
    p[low] = p[0];
    return low;
}

int Search_Bin(int *p, int key, int n)
{
    int mid;
    int low = 1;
    int high = n;
    int judge = 0;
    while( low <= high )
    {
        mid = (low + high) / 2;
        if(p[mid] == key){
            printf("%d\n", key);
            judge = 1;
            break;
        }
        else if(key < p[mid])
            high = mid-1;
        else
            low = mid+1;
    }
    if(judge == 0)
        printf("Not found!\n");
    return 0;
}

int main()
{
    int i, n, key1, key2;
    int *p;
    printf("Input the number of series:");
    scanf("%d", &n);
    p = (int*)malloc((n+1)*sizeof(int));
    printf("Input the series:\n");
    for(i = 1; i <= n; i++)
        scanf("%d", &p[i]);
    QSort(p, 1, n);
    for(i = 1; i <= n; i++)
        printf("%d ", p[i]);
    printf("\n");
    printf("Input two figures what you want:\n");
    scanf("%d %d", &key1, &key2);
    Search_Bin(p, key1, n);
    Search_Bin(p, key2, n);
    return 0;
}