Python Program Finds Missing Number in Sequence

Day 20 of my #100DaysOfCode challenge 🚀 Today I worked on a Python program to find the missing number in a sequence of natural numbers. The goal was to solve the problem efficiently using a mathematical formula instead of looping through numbers manually. What the program does: • Takes a list of numbers with one missing value • Calculates the expected sum of first n natural numbers • Calculates the actual sum of the given list • Finds the missing number by subtracting both sums How the logic works: Since one number is missing, the total count should be len(numbers) + 1 The formula for sum of first n natural numbers is used: n * (n + 1) // 2 The actual sum of the list is calculated using sum() The missing number is found using: expected_sum - actual_sum The result is printed Example: Input list:[1, 2, 3, 5, 6, 7, 8] Output: Missing number: 4 Key learnings from Day 20: – Using mathematical formulas for optimization – Reducing time complexity to O(n) – Avoiding unnecessary loops – Strengthening problem-solving approach #100DaysOfCode #Day20 #Python #PythonProgramming #Algorithms #ProblemSolving #CodingPractice #LogicBuilding #LearnByDoing #ComputerScience #BTech #CSE #AIandML #VITBhopal #TechJourney

  • graphical user interface, text

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