StreakPeaked· Practice

ExamsGATETechnical

Consider the following function: int unknown(int n){ int i, j, k=0; for (i=n/2; i<=n; i++) for (j=2; j<=n; j=j*2) k = k + n/2; return (k); } The return value of the function is

  1. Θ(n²)
  2. Θ(n² log n)
  3. Θ(n³)
  4. Θ(n³ log n)

Correct answer: Θ(n² log n)

Solution

The function has two nested loops: the outer loop runs for n/2 to n, which is Θ(n), and the inner loop runs logarithmically with respect to n (specifically, it doubles j each iteration). Therefore, the total complexity is the product of these two, resulting in Θ(n² log n).

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