title: Count Distinct Occurrences As A Subsequence
signature: function countDistinctOccurrencesAsASubsequence($s, $t) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($s, $t, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($s, $t), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        "banana", "ban", 
        3));
      
      printf("TEST-1...%s\n",driver(
        "49597223", "42", 
        2));
      
      printf("TEST-2...%s\n",driver(
        "1000010000011", "010", 
        20));
      
      printf("TEST-3...%s\n",driver(
        "BTlzufK", "EpsVuzP lf", 
        0));
      
      printf("TEST-4...%s\n",driver(
        "3474007", "370", 
        2));
      
      printf("TEST-5...%s\n",driver(
        "0010", "00000", 
        0));
      
      printf("TEST-6...%s\n",driver(
        "dKHhoTD", "doT", 
        1));
      
      printf("TEST-7...%s\n",driver(
        "9123259723", "123", 
        4));
      
      printf("TEST-8...%s\n",driver(
        "11001000111110", "0", 
        6));
      
      printf("TEST-9...%s\n",driver(
        "iY WJlIZ", "iI", 
        1));
      
  }
  
  main();
  ?>
source_py: def count_distinct_occurrences_as_a_subsequence(S, T):
      m = len(T)
      n = len(S)
      if (m > n):
          return 0
      mat = [[0 for _ in range((n + 1))] for __ in range((m + 1))]
      for i in range(1, (m + 1)):
          mat[i][0] = 0
      for j in range((n + 1)):
          mat[0][j] = 1
      for i in range(1, (m + 1)):
          for j in range(1, (n + 1)):
              if (T[(i - 1)] != S[(j - 1)]):
                  mat[i][j] = mat[i][(j - 1)]
              else:
                  mat[i][j] = (mat[i][(j - 1)] + mat[(i - 1)][(j - 1)])
      return mat[m][n]
source_cpp: int count_distinct_occurrences_as_a_subsequence(string S, string T) {
    int m = T . length ( ), n = S . length ( );
    if ( m > n ) return 0;
    int mat [ m + 1 ] [ n + 1 ];
    for ( int i = 1;
    i <= m;
    i ++ ) mat [ i ] [ 0 ] = 0;
    for ( int j = 0;
    j <= n;
    j ++ ) mat [ 0 ] [ j ] = 1;
    for ( int i = 1;
    i <= m;
    i ++ ) {
      for ( int j = 1;
      j <= n;
      j ++ ) {
        if ( T [ i - 1 ] != S [ j - 1 ] ) mat [ i ] [ j ] = mat [ i ] [ j - 1 ];
        else mat [ i ] [ j ] = mat [ i ] [ j - 1 ] + mat [ i - 1 ] [ j - 1 ];
      }
    }
    return mat [ m ] [ n ];
  }