Shuffle an Array

1. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 2 3 4 5 6 7 8 9 2 10 J random integer = 7

2. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 3 5 4 5 3 6 7 8 2 10 J random integer = 3

3. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 4 J 3 6 7 8 2 10 J 4 random integer = 9

4. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 3 4 6 7 8 2 10 4 3 random integer = 9

5. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 6 8 7 8 6 2 10 3 random integer = 6

6. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 7 3 6 2 10 3 7 random integer = 9

7. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 3 6 10 2 10 6 7 random integer = 8

8. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 3 10 2 7 6 7 2 random integer = 9

9. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 3 10 7 6 6 2 random integer = 8

10. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 3 10 7 6 2 2 random integer = 9

11. Shuffle an Array • Shuffle a deck of cards. • In ith iteration, choose a random element from remainder of deck and put at index i. • choose random integer r between i and N-1 • swap values in positions r and i Array index 0 1 2 3 4 5 6 7 8 9 Value 9 5 J 4 8 3 10 7 6 2