Find First and Last Position of Element in Sorted Array – LeetCode Solution Java , Python 3, Python 2 , C , C++, Best and Optimal Solutions , All you need.
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] <= 109numsis a non-decreasing array.-109 <= target <= 109
C++ Find First and Last Position of Element in Sorted Array LeetCode Solution
vector<int> searchRange(vector<int>& nums, int target) {
int idx1 = lower_bound(nums, target);
int idx2 = lower_bound(nums, target+1)-1;
if (idx1 < nums.size() && nums[idx1] == target)
return {idx1, idx2};
else
return {-1, -1};
}
int lower_bound(vector<int>& nums, int target) {
int l = 0, r = nums.size()-1;
while (l <= r) {
int mid = (r-l)/2+l;
if (nums[mid] < target)
l = mid+1;
else
r = mid-1;
}
return l;
}
Java Find First and Last Position of Element in Sorted Array LeetCode Solution
public class Solution {
public int[] searchRange(int[] nums, int target) {
int[] result = new int[2];
result[0] = findFirst(nums, target);
result[1] = findLast(nums, target);
return result;
}
private int findFirst(int[] nums, int target){
int idx = -1;
int start = 0;
int end = nums.length - 1;
while(start <= end){
int mid = (start + end) / 2;
if(nums[mid] >= target){
end = mid - 1;
}else{
start = mid + 1;
}
if(nums[mid] == target) idx = mid;
}
return idx;
}
private int findLast(int[] nums, int target){
int idx = -1;
int start = 0;
int end = nums.length - 1;
while(start <= end){
int mid = (start + end) / 2;
if(nums[mid] <= target){
start = mid + 1;
}else{
end = mid - 1;
}
if(nums[mid] == target) idx = mid;
}
return idx;
}
}
Python 3 Find First and Last Position of Element in Sorted Array LeetCode Solution
class Solution(object):
#### Main function
def searchRange(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
result = [-1, -1] #1
result[0] = self.findStartingIndex(nums, target) #2
result[1] = self.findEndingIndex(nums, target) #3
return result #4
#### Helper function 1
def findStartingIndex(self, nums, target):
index = -1 #5
low, high = 0, len(nums) -1 #6
while low <= high: #7
mid = low + (high - low)/2 #8
if nums[mid] == target: #9
index = mid #10
high = mid - 1 #11
elif nums[mid] > target: #12
high = mid - 1 #13
else: #14
low = mid + 1 #15
return index
#### Helper function 2
def findEndingIndex(self, nums, target):
index = -1
low, high = 0, len(nums) -1
while low <= high:
mid = low + (high - low)/2
if nums[mid] == target:
index = mid
low = mid + 1 #16
elif nums[mid] > target:
high = mid - 1
else:
low = mid + 1
return index
Array-1180
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Linked List-69
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