拉格朗日插值查找法

#include<iostream>

using namespace std;

int search(const int*, int, int);

int main()

{

int arr[6] = {1,2,3,4,10,20};

int find = search(arr, 6, 10);

if(find == -1)

cout << "没有找到!" << endl;

else

cout << arr[find] << endl;

return 0;

}

int search(const int* arr, int size, int key)

{

int tou, wei, zhong;

tou = 0;

wei = size - 1;

while(tou <= wei)

{

zhong = tou + (wei - tou) * (key - arr[tou]) / (arr[wei] - arr[tou]);  //拉法朗日算法

if(key == arr[zhong])

{

return zhong;

}

else if(key < arr[zhong])

{

wei = zhong - 1;

}

else

tou = zhong + 1;

}

return -1;

}