title: Count Strings Adjacent Characters Difference One
signature: class Solution {
  
      public Long countStringsAdjacentCharactersDifferenceOne(Integer n) {
test_code: import static java.util.Map.entry;  
  import java.util.*;
  import java.lang.*;
  // TESTING CODE 
  // ============================================
  class QuestionEvaluator {
      public static String validateSolution(Integer n, Long expected){
          try{
              Driver driver = new Driver();
              if (driver.run(n,expected)){
                  return "PASSED";
              }
              return "FAILED";
              
          } catch (Exception exception_obj){
              return exception_obj.getClass().getSimpleName();
          }
  
      }
      public static void main(String[] args) {
          String result;
          result = validateSolution(7, 1468L);
          System.out.println(String.format("%s%s","TEST-0...",result));    
      
          result = validateSolution(47, 1134264891541288L);
          System.out.println(String.format("%s%s","TEST-1...",result));    
      
          result = validateSolution(56, 544505079089235836L);
          System.out.println(String.format("%s%s","TEST-2...",result));    
      
          result = validateSolution(22, 41103600L);
          System.out.println(String.format("%s%s","TEST-3...",result));    
      
      }
  }
  
  class Driver{
      public boolean run(Integer n, Long expected){
  
          PLACEHOLDER_CLS_NAME sol = new PLACEHOLDER_CLS_NAME();
          return validateSolution(sol.PLACEHOLDER_FN_NAME(n),expected);
      }
      
      public boolean validateSolution(Long actual, Long expected){
          return actual.equals(expected);
      }
  }
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
source_py: def count_strings_adjacent_characters_difference_one(n):
      dp = [[0 for j in range(27)] for i in range((n + 1))]
      for i in range(0, 26):
          dp[1][i] = 1
      for i in range(2, (n + 1)):
          for j in range(0, 26):
              if (j == 0):
                  dp[i][j] = dp[(i - 1)][(j + 1)]
              else:
                  dp[i][j] = (dp[(i - 1)][(j - 1)] + dp[(i - 1)][(j + 1)])
      sum = 0
      for i in range(0, 26):
          sum = (sum + dp[n][i])
      return sum
source_cpp: int count_strings_adjacent_characters_difference_one(int n) {
    long int dp [ n + 1 ] [ 27 ];
    memset ( dp, 0, sizeof ( dp ) );
    for ( int i = 0;
    i <= 25;
    i ++ ) dp [ 1 ] [ i ] = 1;
    for ( int i = 2;
    i <= n;
    i ++ ) {
      for ( int j = 0;
      j <= 25;
      j ++ ) if ( j == 0 ) dp [ i ] [ j ] = dp [ i - 1 ] [ j + 1 ];
      else dp [ i ] [ j ] = ( dp [ i - 1 ] [ j - 1 ] + dp [ i - 1 ] [ j + 1 ] );
    }
    long int sum = 0;
    for ( int i = 0;
    i <= 25;
    i ++ ) sum = ( sum + dp [ n ] [ i ] );
    return sum;
  }