#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#define N 1024
void search1(int a[N], int num)//二分法插值查找
{
int tou = 0;
int wei = N - 1;
int zhong;
int flag = -1;//假定一开始找不到
int ci = 0;
while (tou <= wei)
{
zhong = (tou + wei) / 2;
//zhong=tou+(wei-tou)*(1/2)
printf("
%d %d %d %d", tou, wei, zhong, ++ci);
if (num == a[zhong])
{
printf("Find! a[%d]=%d", zhong, num);
flag = 1;
break;
}
else if (num > a[zhong])
{
tou = zhong + 1;
}
else
{
wei = zhong - 1;
}
}
if (flag == -1)
{
printf("Not Find!");
}
}
void search2(int a[N], int num)//拉格朗日查找
{
int tou = 0;
int wei = N - 1;
int zhong;
int flag = -1;//假定一开始找不到
int ci = 0;
while (tou <= wei)
{
//zhong = (tou + wei) / 2;
zhong = tou + (wei - tou)*1.0*(num-a[tou])/(a[wei]-a[tou]);//*1.0 乘以一个实数 避免产生误差
printf("
%d %d %d %d", tou, wei, zhong, ++ci);
if (num == a[zhong])
{
printf("Find! a[%d]=%d", zhong, num);
flag = 1;
break;
}
else if (num > a[zhong])
{
tou = zhong + 1;
}
else
{
wei = zhong - 1;
}
}
if (flag == -1)
{
printf("Not Find!");
}
}
void main()
{
int a[N];
for (int i = 0; i < 1024; i++)
{
a[i] = i;
//printf("%d ", a[i]);
}
int num;
scanf("%d", &num);
search2(a, num);//调用函数查找
system("pause");
}
将插值比例1/2换成其他值实现拉格朗日插值查找
由来：拉格朗日插值公式
数据均匀排布的情况下 一次找到
数据不均匀排布的情况下 找到的次数在一次和二分查找法之间