title: Find The First Missing Number
signature: function findTheFirstMissingNumber($array, $start, $end_arg2) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($array, $start, $end_arg2, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($array, $start, $end_arg2), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        array(3, 6, 7, 9, 11, 14, 18, 30, 30, 32, 32, 34, 37, 44, 45, 45, 48, 48, 48, 52, 58, 60, 63, 67, 69, 69, 81, 83, 87, 89, 97, 99), 24, 18, 
        19));
      
      printf("TEST-1...%s\n",driver(
        array(88, -62, 16, 80, 66, 78, 88, 38, 52, -96, 48, 98, 96, -62, 18, 34, -58, 30, -10, 26, -98, 48, -96, 4, 92, 36, 36, -36, -32, -70, 62, -58, -58, -84, 86, -98), 19, 26, 
        19));
      
      printf("TEST-2...%s\n",driver(
        array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 26, 28, 
        26));
      
      printf("TEST-3...%s\n",driver(
        array(79, 99, 79, 85, 61, 58, 62, 61, 39, 87, 39, 74, 36, 70, 30, 43, 20, 52, 54, 50, 81, 98, 42), 20, 20, 
        20));
      
      printf("TEST-4...%s\n",driver(
        array(-98, -72, -46, -44, -42, -40, -16, -4, 62, 70, 74), 8, 10, 
        8));
      
      printf("TEST-5...%s\n",driver(
        array(1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0), 26, 23, 
        24));
      
      printf("TEST-6...%s\n",driver(
        array(58), 0, 0, 
        0));
      
      printf("TEST-7...%s\n",driver(
        array(4, -84, -42, 12, -50, 42, -36, -38, -36, 98, -2, 20, 6, -96, -78, 24, 34, 88, 0, 74, 0, -8, -86, -68, -42, 98, -26, 86, -70, -32, -82, 78, 46, 58, 84, 4, -60, -90, -52, -78), 37, 31, 
        32));
      
      printf("TEST-8...%s\n",driver(
        array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 28, 28, 
        28));
      
      printf("TEST-9...%s\n",driver(
        array(8), 0, 0, 
        0));
      
  }
  
  main();
  ?>
source_py: def find_the_first_missing_number(array, start, end):
      if (start > end):
          return (end + 1)
      if (start != array[start]):
          return start
      mid = int(((start + end) / 2))
      if (array[mid] == mid):
          return find_the_first_missing_number(array, (mid + 1), end)
      return find_the_first_missing_number(array, start, mid)
source_cpp: int find_the_first_missing_number(vector<int> array, int start, int end) {
    if ( start > end ) return end + 1;
    if ( start != array [ start ] ) return start;
    int mid = ( start + end ) / 2;
    if ( array [ mid ] == mid ) return find_the_first_missing_number ( array, mid + 1, end );
    return find_the_first_missing_number ( array, start, mid );
  }