Minimum Number of Moves to Make Palindrome LeetCode solution in Java

1
class Solution {
2

3
  public int minMovesToMakePalindrome(String s) {
4
    int len = s.length();
5
    char[] strArr = s.toCharArray();
6
    int steps = 0;
7
    int l = 0, r = len - 1; // use two pointers l for left and r for right.
8

9
    while (l < r) {
10
      if (strArr[l] == strArr[r]) { // Both characters are equal. so keep going futher.
11
        l++;
12
        r--;
13
      } else { // Both characters are not equal.
14
        int k = r;
15
        k =
16
            findKthIndexMatchingwithLthIndex(
17
                strArr, l, k); // loop through k, until char at index k = char at index l
18

19
        if (k == l) { // we did not find any char at k = char at index l
20
          swap(strArr, l);
21
          steps++;
22
        } else {
23
          while (k < r) {
24
            swap(strArr, k);
25
            steps++;
26
            k++;
27
          }
28
          l++;
29
          r--;
30
        }
31
      } // end of else
32
    } // end of while
33
    System.out.println("palindrome: " + String.valueOf(strArr));
34
    return steps;
35
  }
36

37
  public int findKthIndexMatchingwithLthIndex(char[] strArr, int l, int k) {
38
    while (k > l) {
39
      if (strArr[k] == strArr[l]) {
40
        return k;
41
      }
42
      k--;
43
    }
44
    return k;
45
  }
46

47
  public void swap(char[] strArr, int l) {
48
    if (l + 1 < strArr.length) {
49
      char tempCh = strArr[l];
50
      strArr[l] = strArr[l + 1];
51
      strArr[l + 1] = tempCh;
52
    }
53
  }
54
}