【Search in Rotated Sorted Array II 】cpp

题目：

Follow up for "Search in Rotated Sorted Array":
What if duplicates are allowed?

Would this affect the run-time complexity? How and why?

Write a function to determine if a given target is in the array.

代码：

class Solution {
public:
bool search(vector<int>& nums, int target) {
nums.erase(std::unique(nums.begin(), nums.end()),nums.end());
int begin=0, end=nums.size()-1;
while ( begin<=end )
{
int mid = (begin+end)/2;
if ( nums[mid]==target ) return true;
// first half sorted
if ( nums[begin]<=nums[mid] )
{
if ( target>nums[mid] )
{
begin = mid+1;
}
else
{
if ( target>=nums[begin] )
{
end = mid-1;
}
else
{
begin = mid+1;
}
}
continue;
}
// second half sorted
if ( nums[mid]<nums[end] )
{
if ( target<nums[mid])
{
end = mid-1;
}
else
{
if ( target<=nums[end])
{
begin = mid+1;
}
else
{
end = mid-1;
}
}
}

}
return false;
}
};

tips：

通过这题熟悉了stl将vector去重的方法。

采用了偷懒的做法：

1. 先利用stl的unqiue把数组去重

2. 再按照Search in Rotated Sorted Array这题的方法进行二分查找。