Greedy Algorithms - Minimum Domino Rotations
Given the following code and input arrays A = [2,1,2,4,2,2], B = [5,2,6,2,3,2], what is the output of minDominoRotations(A, B)?
Given the following code and input arrays A = [2,1,2,4,2,2], B = [5,2,6,2,3,2], what is the output of minDominoRotations(A, B)?
easy🧾 Code Trace Q3 of Q15
Step-by-Step Solution
Solution:
Step 1: Check candidate A[0] = 2
Count rotations needed to make all dominoes 2 on top or bottom.Step 2: Count rotations
Rotations on top: positions 1 and 3 need rotation (2 rotations), rotations on bottom: positions 1,3,4 need more (3 rotations). Minimum is 2.Step 3: Check candidate B[0] = 5 if needed
Since rotations for A[0] candidate is not -1, no need to check B[0].Final Answer:
Option C -> Option CQuick Check:
Output matches minimal rotations counted [OK]
Quick Trick: Check rotations for candidate on first domino [OK]
Common Mistakes:
MISTAKES- Miscounting rotations or returning -1 prematurely
Trap Explanation:
PITFALL- Candidates often confuse which side needs rotation or miss counting correctly.
Interviewer Note:
CONTEXT- Tests code tracing and rotation counting accuracy.
Master "Minimum Domino Rotations" in Greedy Algorithms
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