代码面试题：Majority Number

Given an array of integers, the majority number is the number that occurs more than half of the size of the array. Find it.

Example

For [1, 1, 1, 1, 2, 2, 2], return 1

思路：将不同的元素凑对，剩下的元素则为答案。用到两两抵消的思想。

public int majorityNumber(int[] A){
    	if (A == null || A.length == 0) {
    		return -1;
    	}
    	
    	int candidate = 0;
    	int count = 0;
    	for (int i = 0; i < A.length; i++) {
    		if (count == 0) {
    			candidate = A[i];
    		}
    		if (candidate == A[i]) {
    			count++;
    		} else count--;
    	}
    	return candidate;
    }