查找

int[] arr={33, 22, 11, 44, 55, 66};

无序查找

public int getNum(int[] arr,int num){
    for(int i=0;i<arr.length-1;i++){
    	if(num==arr[i]){
    		return i;
    	}
    }
    return -1;
}

二分查找

public static int binearSearch(int[] arr,int num){
    int min=0;
    int max=arr.length-1;
    while(min<max){
        int mid=(min+max)/2;
        if(num>arr[mid]){
            min=mid+1;
        }else if(num<arr[mid]){
            max=mid-1;
        }else{
            return mid;
        }
    }
    return -1;
}