11.3---旋转有序数组之后查找元素（CC150）

public static int findElement(int[] a, int n,int key){
        int left = 0;
        int right = a.length - 1;
        while(left <= right){
            int mid = (left + right) / 2;
            if(key == a[mid]) return mid;
            if(a[left] <= a[mid]){
                if(key <= a[mid] && key >= a[left]){
                    right = mid -1;
                }
                else{
                    left = mid + 1;
                }
            }
            else{
                if(key > a[mid] && key < a[right]){
                    left = mid + 1;
                }
                else{
                right = mid -1;
                }
            }
        }

        return -1;
    }