Leetcode Find Peak Element

class Solution {
public:
int findPeakElement(const vector<int> &num) {
int size = num.size();
if(size==1){
return 0;
}else{
int i=0,j=size-1;
while(i<j){
if(num[i]>num[i+1]){
return i;
}
if(num[j-1]<num[j]){
return j;
}
int mid = i + ((j-i)>>1);
if(num[mid+1]>num[mid]){
i = mid + 1;
}else
if(num[mid+1]<num[mid]){
j = mid;
}else{
i++;j--;
}
}
}
}
};