Given a sorted array consisting of only integers where every element appears twice except for one element which appears once. Find this single element that appears only once.
有序襟诸，連續(xù)，考慮二分法轻抱，時間是LOGN，注意這里的判斷條件要復雜一點恩沛，應該是根據(jù)坐標的奇偶性和相等元素位于前還是后來判斷取左側(cè)還是右側(cè)。
class Solution {
public int singleNonDuplicate(int[] nums) {
if(nums.length==1)return nums[0];
int lo = 0 ;
int hi = nums.length-1;
int result = 0;
while(lo<=hi)
{
int mid = lo+(hi-lo)/2;
if(mid!=lo&&mid!=hi)
{
if(nums[mid]!=nums[mid-1]&&nums[mid]!=nums[mid+1])
{
result=nums[mid];
break;
}
else if(nums[mid]==nums[mid-1])
{
if((mid&1)==1)
lo=mid+1;
else
hi=mid-2;
}
else
{
if((mid&1)==0)
lo=mid+2;
else
hi=mid-1;
}
}
else
{
if(lo==hi)
{
result=nums[mid];
break;
}
}
}
return result;
}
}
