05 August 2008
排好序的数组中找出只出现一次的元素，别的都是出现两次，二分查找，136位操作那个是没排序的
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
class Solution {
/**
[1,1,2,3,3,4,4,8,8]
*/
public int singleNonDuplicate(int[] nums) {
int start = 0, end = nums.length - 1;
while (start < end) {
// We want the first element of the middle pair,
// which should be at an even index if the left part is sorted.
int mid = start + (end - start)/2;
if (mid % 2 == 1) {
mid--;
}
if (nums[mid] != nums[mid+1]) {//didn't find a pair. The single element must be on the left.
end = mid;
} else {// found a pair. The single element must be on the right.
start = mid + 2;
}
}
// 'start' should always be at the beginning of a pair.
// When 'start > end', start must be the single element.
return nums[start];
}
}