Array Transformation using Bubble Sort Technique

-
Problem is here: https://leetcode.com/problems/array-transformation/

Given an initial array arr, every day you produce a new array using the array of the previous day.
On the i-th day, you do the following operations on the array of day i-1 to produce the array of day i:
  1. If an element is smaller than both its left neighbor and its right neighbor, then this element is incremented.
  2. If an element is bigger than both its left neighbor and its right neighbor, then this element is decremented.
  3. The first and last elements never change.
After some days, the array does not change. Return that final array.

Example 1:
Input: arr = [6,2,3,4]
Output: [6,3,3,4]
Explanation: 
On the first day, the array is changed from [6,2,3,4] to [6,3,3,4].
No more operations can be done to this array.
Example 2:
Input: arr = [1,6,3,4,3,5]
Output: [1,4,4,4,4,5]
Explanation: 
On the first day, the array is changed from [1,6,3,4,3,5] to [1,5,4,3,4,5].
On the second day, the array is changed from [1,5,4,3,4,5] to [1,4,4,4,4,5].
No more operations can be done to this array.

Constraints:
  • 1 <= arr.length <= 100
  • 1 <= arr[i] <= 100

One way to solve is by using the same overall technique of a bubble sort algorithm, which in pseudo code would be:

Done = False
While Not Done
  Done = True
  For each index from  0..N-1
    If A[index] > A[index+1]
      Swap, and Mark Done = False

 You can use the same technique for this problem. It is N^2, but since N = 100, it shouldn't be a problem. Code is below, cheers, ACC.

public class Solution
{
    public IList<int> TransformArray(int[] arr)
    {
        int[] next = new int[arr.Length];
        int[] prev = (int[])arr.Clone();

         bool done = false;
        while (!done)
        {
            next[0] = prev[0];
            next[next.Length - 1] = prev[prev.Length - 1];

             done = true;
            for (int i = 1; i < next.Length - 1; i++)
            {
                next[i] = prev[i];
                if (next[i] < prev[i - 1] && next[i] < prev[i + 1])
                {
                    next[i]++;
                    done = false;
                }
                else if (next[i] > prev[i - 1] && next[i] > prev[i + 1])
                {
                    next[i]--;
                    done = false;
                }
            }

             prev = (int[])next.Clone();
        }

         return next.ToList<int>();
    }
}

Comments

Post a Comment

Popular posts from this blog

Count Binary Substrings

-
Image
Problem by Leetcode:  https://leetcode.com/problems/count-binary-substrings/description/ Give a string  s , count the number of non-empty (contiguous) substrings that have the same number of 0's and 1's, and all the 0's and all the 1's in these substrings are grouped consecutively. Substrings that occur multiple times are counted the number of times they occur. Example 1: Input: "00110011" Output: 6 Explanation: There are 6 substrings that have equal number of consecutive 1's and 0's: "0011", "01", "1100", "10", "0011", and "01". Notice that some of these substrings repeat and are counted the number of times they occur. Also, "00110011" is not a valid substring because all the 0's (and 1's) are not grouped together. Example 2: Input: "10101" Output: 4 Explanation: There are 4 substrings: "10", "01", "10", "01&
Read more

Count Vowels Permutation: Standard DP

-
Image
Standard DP problem:  https://leetcode.com/problems/count-vowels-permutation/ Given an integer  n , your task is to count how many strings of length  n  can be formed under the following rules: Each character is a lower case vowel ( 'a' ,  'e' ,  'i' ,  'o' ,  'u' ) Each vowel  'a'  may only be followed by an  'e' . Each vowel  'e'  may only be followed by an  'a'  or an  'i' . Each vowel  'i'   may not  be followed by another  'i' . Each vowel  'o'  may only be followed by an  'i'  or a  'u' . Each vowel  'u'  may only be followed by an  'a'. Since the answer may be too large, return it modulo  10^9 + 7. Example 1: Input: n = 1 Output: 5 Explanation: All possible strings are: "a", "e", "i" , "o" and "u". Example 2: Input: n = 2 Output: 10 Explanation: All possible strings are
Read more

Maximum Number of Balloons

-
Image
#431 in my solved list:  https://leetcode.com/problems/maximum-number-of-balloons/ Given a string  text , you want to use the characters of  text  to form as many instances of the word  "balloon"  as possible. You can use each character in  text   at most once . Return the maximum number of instances that can be formed.   Example 1: Input: text = "nlaebolko" Output: 1 Example 2: Input: text = "loonbalxballpoon" Output: 2 Example 3: Input: text = "leetcode" Output: 0 Constraints: 1 <= text.length <= 10^4 text  consists of lower case English letters only. Solution is as follows:  - Count the number of occurrences of the "balloon" letters in the input string  - For "l" and "o", divide the count by 2  - If the balloon string is not fully covered, return 0  - Return the min number across all occurrences Code is below, cheers, ACC. public class Solution {     public int M
Read more