折半查找

最新推荐文章于 2024-11-11 23:49:41 发布

原创最新推荐文章于 2024-11-11 23:49:41 发布 · 592 阅读

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本文介绍了一种改进的折半查找算法，并通过C语言实现了一个实例。重点在于优化查找过程，提高效率。

#include <stdio.h>
/*练习3-1改进折半查找*/
int binsearch(int x, int v[], int n);

int main()
{
	int v[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
	printf("%d\n", binsearch(9, v, 10));
	return 0;
}

/* 
binsearch: find x in v[0] <= v[1] <= ... <= v[n1]
*/
int binsearch(int x, int v[], int n)
{
	int low, high, mid;
	low = 0;
	high = n-1;
	
	while (low < high) {
		mid = (low+high)/2;
		
		if (x <= v[mid])
			high = mid;//上限只能在high之内
		else
			low = mid + 1;//下限在low之后
	}
	
	return (x == v[low])?low:-1;

}