SNELECTP - Editorial

editorial
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Problem Link - Snakes, Mongooses and the Ultimate Election in Greedy Algorithms

Problem Statement:

In Snakeland, snakes (‘s’) and mongooses (‘m’) are lined up in a row. They will hold an election to decide the winner. Mongooses cheat by eating at most one neighboring snake before the vote.

You need to determine the winner after the mongooses eat the maximum possible number of snakes.

  • If snakes outnumber mongooses, snakes win.
  • If mongooses outnumber snakes, mongooses win.
  • If both are equal, it’s a tie.

Approach:

  • Observation:
  • Mongooses can eat at most one neighboring snake, either to the left or right, but not both.
  • Our goal is to maximize the number of snakes eaten by mongooses before counting votes.
  • Simulating Mongooses Eating Snakes:
  • For each mongoose ('m'), check its immediate neighbors (left and right).
  • If there’s a snake ('s') next to it that hasn’t been eaten yet, the mongoose will eat that snake.
  • This ensures that mongooses eat as many snakes as possible, which may reduce the number of snakes counted in the final election.
  • Counting Remaining Snakes and Mongooses:
  • After mongooses have eaten the maximum possible number of neighboring snakes, count how many snakes and mongooses are left.
  • Determine the Outcome:
  • Compare the final number of mongooses and snakes:
    • If the number of mongooses is greater, mongooses win.
    • If the number of snakes is greater, snakes win.
    • If both numbers are equal, it results in a tie.

Complexity:

  • Time Complexity: O(N) Traversing the string 2 times → 2*O(N)
  • Space Complexity: O(1)