"""

Question Denoscription
    Given an input string s, reverse the order of the words.

    A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.

    Return a string of the words in reverse order concatenated by a single space.

    Note that s may contain leading or trailing spaces or multiple spaces between two words. 
    The returned string should only have a single space separating the words. Do not include any extra spaces.



    Example 1:

    Input: s = "the sky is blue"
    Output: "blue is sky the"
    Example 2:

    Input: s = "  hello world  "
    Output: "world hello"
    Explanation: Your reversed string should not contain leading or trailing spaces.
    Example 3:

    Input: s = "a good   example"
    Output: "example good a"
    Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.
 

Constraints:

    1 <= s.length <= 104
    s contains English letters (upper-case and lower-case), digits, and spaces ' '.
    There is at least one word in s.
    
    
    "a good   example"
["a","good","example"]
      L  R
 
 
 [example,"good","a"]


"""

#will s will split
#variables left->0 rght ->len(splited)-1
#will have  a while l<L    left+=1 righ-=1 


def revercing_word(s):
    words=[] 
    for word in s.split(" "):
        if word:
            words.append(word)
    
    left=0
    right=len(words)-1
    
    
    while left<right:
        words[left],words[right]= words[right],words[left]
        left+=1
        right-=1
        
    return " ".join(words)
print(revercing_word("hello world"))

You are given an integer array nums and an integer k. Find the maximum subarray sum of all the subarrays of nums that meet the following conditions:

The length of the subarray is k, and
All the elements of the subarray are distinct.
Return the maximum subarray sum of all the subarrays that meet the conditions. If no subarray meets the conditions, return 0.

A subarray is a contiguous non-empty sequence of elements within an array.

 

Example 1:

Input: nums = [1,5,4,2,9,9,9], k = 3
Output: 15
Explanation: The subarrays of nums with length 3 are:
- [1,5,4] which meets the requirements and has a sum of 10.
- [5,4,2] which meets the requirements and has a sum of 11.
- [4,2,9] which meets the requirements and has a sum of 15.
- [2,9,9] which does not meet the requirements because the element 9 is repeated.
- [9,9,9] which does not meet the requirements because the element 9 is repeated.
We return 15 because it is the maximum subarray sum of all the subarrays that meet the conditions
Example 2:

Input: nums = [4,4,4], k = 3
Output: 0
Explanation: The subarrays of nums with length 3 are:
- [4,4,4] which does not meet the requirements because the element 4 is repeated.
We return 0 because no subarrays meet the conditions.
 

Constraints:

1 <= k <= nums.length <= 105
1 <= nums[i] <= 105

You are given a 0-indexed integer array nums.
Swaps of adjacent elements are able to be performed on nums.
A valid array meets the following conditions:
    The largest element (any of the largest elements if there are multiple) is at the rightmost position in the array.
    The smallest element (any of the smallest elements if there are multiple) is at the leftmost position in the array.
Return the minimum swaps required to make nums a valid array.
 
Example 1:
Input: nums = [3,4,5,5,3,1]
Output: 6
Explanation: Perform the following swaps:
- Swap 1: Swap the 3rd and 4th elements, nums is then [3,4,5,3,5,1].
- Swap 2: Swap the 4th and 5th elements, nums is then [3,4,5,3,1,5].
- Swap 3: Swap the 3rd and 4th elements, nums is then [3,4,5,1,3,5].
- Swap 4: Swap the 2nd and 3rd elements, nums is then [3,4,1,5,3,5].
- Swap 5: Swap the 1st and 2nd elements, nums is then [3,1,4,5,3,5].
- Swap 6: Swap the 0th and 1st elements, nums is then [1,3,4,5,3,5].
It can be shown that 6 swaps is the minimum swaps required to make a valid array.

Example 2:
Input: nums = [9]
Output: 0
Explanation: The array is already valid, so we return 0.

    
          
 
Constraints:
1 <= nums.length <= 10^5
1 <= nums[i] <= 10^5

You are given a sorted array nums of size n and an integer target. 
Your task is to find the pair of numbers in the array whose sum is less than or equal to the target and has the largest possible sum.

Return the maximum sum of such a pair. If no valid pair exists, return -1.

Example 1:
Input: nums = [2, 3, 5, 8, 13], target = 10
Output: 10
 l
[2, 3, 5, 8, 13],
          r
[7,8 , 10]
Explanation: The pair (2, 8) has a sum of 10, which is the largest possible sum less than or equal to 10.

Example 2:
Input: nums = [1, 1, 1, 1], target = 1
Output: -1
Explanation: No pair has a sum less than or equal to 1.

Constraints:
1<=n<=10⁵
Nums  is sorted in non-decreasing order.



def targetSum(nums , target):
    left = 0
    max_ = -1
    right = len(nums)-1
    while left < right:
        sum = nums[left] + nums[right]
        if sum == target:
            return sum
        elif sum > target:
            right -=1
        elif sum < target:
            left += 1
            max_ = max(max_,sum)
    return max_

Mistakes are proof that you’re trying. Embrace every error as a lesson and keep moving forward