title: Find The First Missing Number
signature: func findTheFirstMissingNumber(array []int, start int, end_arg2 int) int {
test_code: package main
  
  import (
      "fmt"
      "reflect"
      "math"
      "sort"
  )
  
  // SOLUTION CODE
  // ===================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE
  // ===================================
  func validateSolution(actual int, expected int) bool {
      return reflect.DeepEqual(actual,expected)
  }
  
  func driver(array []int, start int, end_arg2 int, expected int) string {
      if validateSolution(PLACEHOLDER_FN_NAME(array, start, end_arg2),expected) {
              return "PASSED"
      }
      return "FAILED"
  
  }
  
  func main() {
  
      // Use imports to avoid undefined errors
      var _ = reflect.DeepEqual
      _ = math.Abs
      _ = sort.Sort
      result := ""
      result = driver([]int{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)
      fmt.Printf("TEST-0...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-1...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-2...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-3...%s\n", result)
      
      result = driver([]int{-98, -72, -46, -44, -42, -40, -16, -4, 62, 70, 74}, 
  	8, 
  	10, 8)
      fmt.Printf("TEST-4...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-5...%s\n", result)
      
      result = driver([]int{58}, 
  	0, 
  	0, 0)
      fmt.Printf("TEST-6...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-7...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-8...%s\n", result)
      
      result = driver([]int{8}, 
  	0, 
  	0, 0)
      fmt.Printf("TEST-9...%s\n", result)
      
          
  }
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 );
  }