36 lines
789 B
C++
36 lines
789 B
C++
#include <vector>
|
|
#include <cstdio>
|
|
|
|
/**
|
|
* 540. Single Element in a Sorted Array
|
|
* You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once.
|
|
* Return the single element that appears only once.
|
|
* Your solution must run in O(log n) time and O(1) space.
|
|
*/
|
|
|
|
class Solution {
|
|
public:
|
|
static int singleNonDuplicate(const std::vector<int>& nums) {
|
|
int L = 0, R = nums.size();
|
|
if (R == 1)
|
|
return nums[0];
|
|
|
|
// Interval [L, R)
|
|
while (R - L > 1) {
|
|
int M = (L + R) >> 1;
|
|
if (nums[M] == nums[M ^ 1]) {
|
|
L = 1 + (M | 1);
|
|
} else {
|
|
R = (M & (~1)) + 1;
|
|
}
|
|
}
|
|
|
|
return nums[L];
|
|
}
|
|
};
|
|
|
|
int main() {
|
|
std::printf("%d\n", Solution::singleNonDuplicate({1,1,2,3,3}));
|
|
return 0;
|
|
}
|