二分查找

		var test = [1, 4, 8, 11, 16];
		var i = 0;
		var j = test.length - 1;
		var k = 0;
		var t = 10;
		var count = 0;
		while(i <= j) {
			k = Math.floor((i + j) / 2);
			count++;
			if(test[k] < t) {
				i = k + 1;
			} else if(test[k] == t) {
				alert(count);
				break;
			} else if(test[k] > t) {
				j = k - 1;
			}
		}
		alert(count + "  " + i + "  " + j + "  " + k);
	 
	

评论

2 楼 liudaoru 2008-11-05  

呵呵，关键是一些边界处理。。。

1 楼 Jatula 2008-11-05  

看不明白，换JAVA测试了一下；
package cn.lake.sf;

public class SplitSecond {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] test={1, 4, 8, 11, 16};
int i=0;
int j=test.length-1;
int k=0;
int t=10;
int count=0;
while(i<=j){
k=(int) Math.floor((i+j)/2);
count++;
if(test[k]<t){
System.err.println(count);
break;
}else if(test[k]>t){
j=k-1;
}
}
System.out.println(count+" "+i+" "+j+" "+k);
}

}