旋转数组的最小数字

class Solution {
public:
    int minNumberInRotateArray(vector<int> rotateArray) {
        if(rotateArray.size()==0)
            return 0;
        
        int index1 = 0;
        int index2 = rotateArray.size()-1;
        int indexMid = index1;
        while(rotateArray[index1] >=  rotateArray[index2]){
            if(index2-index1 ==1){
                indexMid = index2;
                break;
            }
            
            indexMid = (index1+index2)/2;
            if(rotateArray[indexMid] >= rotateArray[index1])
                index1= indexMid;
            else if(rotateArray[indexMid] <= rotateArray[index2])
                index2 = indexMid;
        }
        return rotateArray[indexMid];
    }
};