Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value.
If target is not found in the array, return [-1, -1].
Example 1:
Input: nums = [5,7,7,8,8,10], target = 8
Output: [3,4]
Example 2:
Input: nums = [5,7,7,8,8,10], target = 6
Output: [-1,-1]
Example 3:
Input: nums = [], target = 0
Output: [-1,-1]
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| class Solution
{
public int[] searchRange(int[] nums, int target)
{
int start = 0;
int end = nums.length - 1;
int[] ans = {-1, -1};
//test case is {}
if(nums.length == 0)
{
return ans;
}
while(start <= end)
{
int mid = (start + end) / 2;
if(target == nums[mid])
{
//丢弃右边
end = mid - 1;
}
else if(target < nums[mid])
{
end = mid - 1;
}
else
{
start = mid + 1;
}
}
//考虑 tartget 是否存在，判断我们要找的值是否等于 target 并且是否越界
// if target existed, nums[start] == target
if(start == nums.length || nums[start] != target)
{
return ans;
}
else
{
ans[0] = start;
}
ans[0] = start;
start = 0;
end = nums.length - 1;
while(start <= end)
{
int mid = (start + end) / 2;
if(target == nums[mid])
{
//丢弃左边
start = mid + 1;
}
else if(target < nums[mid])
{
end = mid - 1;
}
else
{
start = mid + 1;
}
}
ans[1] = end;
return ans;
}
}
|