原题链接: https://oj.leetcode.com/problems/majority-element/

public int majorityElement(int[] num) {
    Map<Integer, Integer> numToCount = new HashMap<Integer, Integer>();

    for (int i = 0, len = num.length; i < len; i++) {
        if (numToCount.get(num[i]) != null) {
            numToCount.put(num[i], numToCount.get(num[i]) + 1);
        } else {
            numToCount.put(num[i], 1);
        }
    }

    int majorityNum = 0;
    int maxLen = Integer.MIN_VALUE;

    Iterator<Integer> itr = numToCount.keySet().iterator();

    while (itr.hasNext()) {
        int key = itr.next();
        if (numToCount.get(key) > maxLen) {
            maxLen = numToCount.get(key);
            majorityNum = key;
        }
    }

    return majorityNum;
}