✏️ Explanatory Question

The efficiency of an algorithm is 5n2. If each step takes 1 nanosecond (10−9 seconds), how long will the algorithm take to process an input of size 1000?

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📘 Detailed Answer
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Answer with Explanation

Ans. For n = 1000:

5 × (1000)2 × 10−9 = 5 × 10−3 seconds = 5 milliseconds

💡 Explanation:

First, substitute n = 1000 into the efficiency expression:

5n2 = 5 × (1000)2 = 5 × 1,000,000 = 5,000,000 steps

Since each step takes 1 nanosecond = 10−9 seconds, the total execution time is:

5,000,000 × 10−9 seconds = 5 × 10−3 seconds

Since 10−3 seconds = 1 millisecond, the algorithm takes 5 milliseconds.