Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.
If target is not found in the array, return [-1, -1].
You must write an algorithm with O(log n) runtime complexity.
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]
Constraints:
0 <= nums.length <= 105-109 <= nums[i] <= 109nums is a non-decreasing array.-109 <= target <= 109
class Solution {
public int[] searchRange(int[] nums, int target) {
int[] ans = {-1, -1};
if(nums.length==0){
return ans ;
}
ans[0] = firstOccurence(nums,target);
ans[1] = lastOccurence(nums,target);
return ans ;
}
public int firstOccurence(int[] nums , int target){
int start = 0 ;
int end = nums.length-1;
int ans = -1 ;
while(start<=end){
int mid = (start + end )/2;
if(nums[mid]==target){
ans = mid ;
end = mid-1;
}else if ( target > nums[mid]){
start = mid+1 ;
}else{
end = mid-1 ;
}
}
return ans ;
}
public int lastOccurence(int[] nums , int target){
int start = 0 ;
int end = nums.length-1;
int ans = -1 ;
while(start<=end){
int mid = (start + end )/2;
if(nums[mid]==target){
ans = mid ;
start = mid+1 ;
}else if ( target > nums[mid]){
start = mid+1 ;
}else{
end = mid-1 ;
}
}
return ans ;
}
}
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