java学习笔记之折半查找法（二分法）

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package ;

//折半查找法(二分法)

public class halfSearch {

public static void main(String[] args){

int[] arr = {10,15,16,19,28,96,110,128,199};

int index = halfSaerch(arr,28);

System.out.println("index="+index);

}

public static int halfSaerch(int[] arr,int target){

int max = arr.length-1;

int min = 0;

int mid = (max+min)/2;

while(true){

if(target>arr[mid]){

min = mid+1;

}else if(target<arr[mid]){

max = mid-1;

}else{

return mid;

}

//重新计算中间值

mid = (max+min)/2;

//如果找不到

if(max<min){

return -1;

}

}

}

}