[Solved] You have a sequence of children standing in a line, each with a rating.... Which algorithmic approach guarantees the minimum total candies distributed? | Greedy Algorithms

Greedy Algorithms - Candy Distribution

You have a sequence of children standing in a line, each with a rating. You must distribute candies such that each child has at least one candy, and any child with a higher rating than an immediate neighbor gets more candies than that neighbor. Which algorithmic approach guarantees the minimum total candies distributed?

ATwo-pass greedy: first left-to-right to satisfy left neighbors, then right-to-left to satisfy right neighbors

BBrute force repeated adjustment until no changes occur

CSingle pass greedy from left to right only, assigning candies based on previous child

DDynamic programming with memoization over all subsequences

Step-by-Step Solution

Step 1: Understand the problem constraints
Each child must have at least one candy, and children with higher rating than neighbors must have more candies.
Step 2: Identify algorithm that satisfies both left and right neighbor constraints
Two-pass greedy first ensures left neighbor condition, then right neighbor condition, guaranteeing minimal total candies.
Final Answer:
Option A -> Option A
Quick Check:
Two passes ensure both neighbor constraints met [OK]

Quick Trick: Two passes needed to satisfy both neighbors [OK]

Common Mistakes:

MISTAKES

Using single pass left-to-right misses right neighbor constraints
Assuming brute force is efficient enough
Confusing DP with greedy here

Trap Explanation:

PITFALL

Single pass greedy looks simpler but fails right neighbor checks, making two-pass greedy optimal.

Interviewer Note:

CONTEXT

Tests if candidate recognizes the pattern and why two passes are needed.

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More Greedy Algorithms Quizzes

Which algorithmic approach guarantees the minimum total candies distributed?

Step 1: Understand the problem constraints

Step 2: Identify algorithm that satisfies both left and right neighbor constraints

Final Answer:

Quick Check:

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