C/C++实践笔记 017二分查找、拉格朗日查找、插入排序

一、二分查找法

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<stdio.h>
#define N 1024

void search(int a[N],int num) //二分查找法
{
    int tou = 0;
    int wei = N - 1;
    int zhong;
    int flag = -1;  
    int ci = 0;
    while (tou<=wei)
    {    
        zhong = (tou + wei) / 2;
        if (num==a[zhong]) 
        {    
            ci++;
            printf("找到，a[%d]=%d", zhong, num);
            flag = 1;
            break;
        }
        else if (num > a[zhong])
        {
            tou = zhong + 1;
        }
        else 
        {
            wei = zhong - 1;
        }

    }

    if (flag == -1)
    {
        printf("没有找到");
    }
}

 

二、拉格朗日查找法

 

void searchL(int a[N], int num) //拉格朗日查找法
{
    int tou = 0;
    int wei = N - 1;
    int zhong;
    int flag = -1;
    int ci = 0;
    while (tou <= wei)
    {
        zhong = tou+(wei-tou)*1.0*(num-a[tou])/(a[wei]-a[tou]);
        if (num == a[zhong])
        {
    
            printf("找到，a[%d]=%d,%d", zhong, num,++ci);
            flag = 1;
            break;
        }
        else if (num > a[zhong])
        {
            tou = zhong + 1;
        }
        else
        {
            wei = zhong - 1;
        }

    }

    if (flag == -1)
    {
        printf("没有找到");
    }
}
void main()
{
    int a[N];
    for (int i = 0; i < N; i++)
    {
        a[i] = i;
        printf("%d", i);
    }

    int num;
    scanf("%d", &num);
    searchL(a, num);
    system("pause");
}

 

 

二、插入排序法

#include<stdlib.h>
#include<stdio.h>

void main1() //先写一个插入一个
{
    int a[10] = { 1,2,3,4,6,7,8,9,10,5 };
    int temp = a[9];
    int j = 9;//记录下标

    while (j > 0&& a[j-1]>temp)   //确定要插入的位置
    {
        a[j] = a[j - 1];  //往后移动
        j--;
    }
    a[j] = temp;

    for (int i = 0; i < 10; i++)
    {
        printf("%d", a[i]);

    }
    printf("\n");

    
    
    getchar();




}

void main()
{
    int a[10] = { 1,5,2,4,3,8,7,9,10,6 };
    for (int i = 1; i < 10; i++)  //只有一个不需要插入
    {
        int temp = a[i];
        int j = i;
        while (j > 0 && a[j - 1] > temp)
        {
            a[j] = a[j - 1];
            j--;
        }
        a[j] = temp;
    }
    for (int i = 0; i < 10; i++)
    {
        printf("%d", a[i]);

    }
    getchar();
}