LeetCode34. Search for a range优雅解法

/**
Given a sorted array of integers, find the starting and ending position of a given target value.


Your algorithm's runtime complexity must be in the order of O(log n).


If the target is not found in the array, return [-1, -1].


For example,
Given [5, 7, 7, 8, 8, 10] and target value 8,
return [3, 4].
*/
#include <vector>


using namespace std;


class Solution {
public:
vector<int> searchRange(vector<int>& nums, int target) {
int begin = 0;
int end = nums.size()-1;
vector<int> vs;
while (begin <= end) {
int mid = (begin + end) / 2;
if (nums[mid] == target) {
int min = mid;
while (min >= 0 && nums[mid] == nums[min])
min--;
int max = mid;
while (max <= end && nums[mid] == nums[max]) {
max++;
}
vs.push_back(min+1);
vs.push_back(max - 1);
return vs;
}
else if (nums[mid] > target) {
end = mid - 1;
}
else {
begin = mid + 1;
}
}
vs.push_back(-1);
vs.push_back(-1);
return vs;
}
};