There is an integer array, and it is known that the number of occurrences is more than half. Please use the O (n) Complexity Algorithm to find this number.

There is an integer array, and we know that the number of occurrences of a number is more than half. Please use the complexity of O (n ).AlgorithmFind this number.

Method 1: Hash linked list

Method 2: Use two variables A and B, where a stores the number in an array and B is used to count. At the beginning, Class B is initialized to 0.

Traverse the array,

If B = 0, make a equal to the current number and B equal to 1;

If the current number is the same as that of a, B = B + 1;

If the current number is different from a, B = B-1.

At the end of the traversal, the number in a is the number to be searched.

The time complexity of this algorithm is O (n), and the space complexity is O (1 ).

C LanguageDescription:

 

 

1. IntMain ()
2. {
3. IntI, A, B;
4. IntA [10] = {1, 2, 3, 1, 2, 1, 6, 1 };
6. A = A [5];
7. B = 0;
8. For(I = 0; I <10; I ++)
9. If(B = 0)
10. {
11. A = A [I];
12. B = 1;
13. }ElseIf(A = A [I])
14. B ++;
15. ElseIf(! = A [I])
16. B --;
17. Printf ("% d", );
18. Getchar ();
19. Return0;
20. }