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Enumerating All Permutations - Complete Search | Fundamental Algorithms | Repovive

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Fundamental Algorithms8 sections · 294 units2h total

Open in Course

Enumerating All Permutations

Using library functions or recursion.

Using C++ next_permutation:

sort(arr.begin(), arr.end())
do {
    // process current permutation
} while (next_permutation(arr.begin(), arr.end()))

Using Python itertools:

from itertools import permutations
for perm in permutations(arr):
    # process perm

Manual recursion: Use the backtracking template with used array.

Time: $O(n! \cdot n)$ . There are $n!$ permutations, each taking $O(n)$ to process.

When feasible: $n \leq 10$ gives $\leq 3.6 \times 10^6$ permutations.