二分查找（返回相同元素索性最小）

#include "stdio.h"
int bisearch(int arr[],int n , int value)
{
	int min = 0;
	int max = n-1;
	int mid = 0;
	while( min < max-1)
	{
		mid = max - (max - min)/2;
		if (arr[mid] > value)
		{
			max =mid;
		}
		else if(arr[mid] < value)
		{
			min = mid;
		}
		else 
		{
			max = mid;
		}
	}
	if (arr[min] == value)
	{
		return min;
	}
	else if(arr[max] == value)
	{	
		return max;
	}
	else return -1;
}
void main()
{
	int arr[10] = {1,3,4,5,9,12,12,12,56,98};
	printf("%d" , bisearch(arr,10,12));
}