title: Count Distinct Occurrences As A Subsequence
signature: int countDistinctOccurrencesAsASubsequence(string s, string t) {
test_code: #include <algorithm>
  #include <assert.h>
  #include <cstdlib>
  #include <iostream>
  #include <map>
  #include <set>
  #include <string>
  #include <tuple> 
  #include <unordered_map>
  #include <vector>
  #include <math.h>
  #include <cmath>
  #include <bits/stdc++.h>
  #include <numeric>
  #include <functional>
  
  using namespace std;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(int actual, int expected){
      return actual == expected;
  }
  
  string driver(string s, string t, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(s, t), expected)){
              return "PASSED";
          }
          return "FAILED";
      }
      catch (const std::overflow_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::runtime_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::exception& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (...)
      {
          return "UNK_ERROR";
      }
  }
  
  int main() {
      string result = "";
  
      result = driver("banana", "ban", 3); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver("49597223", "42", 2); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver("1000010000011", "010", 20); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = driver("BTlzufK", "EpsVuzP lf", 0); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = driver("3474007", "370", 2); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      result = driver("0010", "00000", 0); 
      cout << "TEST-" << 5 << "..."
           <<  result
           << "\n";
  
      result = driver("dKHhoTD", "doT", 1); 
      cout << "TEST-" << 6 << "..."
           <<  result
           << "\n";
  
      result = driver("9123259723", "123", 4); 
      cout << "TEST-" << 7 << "..."
           <<  result
           << "\n";
  
      result = driver("11001000111110", "0", 6); 
      cout << "TEST-" << 8 << "..."
           <<  result
           << "\n";
  
      result = driver("iY WJlIZ", "iI", 1); 
      cout << "TEST-" << 9 << "..."
           <<  result
           << "\n";
  
      return 0;
  }
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 ];
  }