【Java】majorityElement

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/** * Created on 16/6/4. */import java.util.Arrays;import java.util.HashMap;public class majorityElement {    public static void main(String[] args) {        int[] x = {1,2,4,4,4,3};        System.out.println(majorityElement(x));        System.out.println(anotherMajorityElement(x));        System.out.println(thirdMajorityElement(x));    }    public static int majorityElement(int[] x) {        Arrays.sort(x);        return x[x.length/2];    }    public static int anotherMajorityElement(int[] x) {        if (x == null || x.length == 0) {            return 0;        }        int major = x[0];        int count = 1;        for (int i = 1; i < x.length; i++) {            if (major == x[i]) {                count++;            } else {                count--;            }            if (count == 0) {                major = x[i];                count = 1;            }        }        return major;    }    public static int thirdMajorityElement(int[] x) {        int len = x.length;        if (len < 3) {            return x[0];        }        int m = (len % 2 == 0) ? len / 2 : len / 2 + 1;        HashMap<Integer, Integer> map = new HashMap<>();        for (int key : x) {            if (!map.containsKey(key)) {                map.put(key, 1);            } else {                int count = map.get(key);                if (count + 1 > m) {                    return key;                }                map.put(key, count + 1);            }        }        return 0;    }}
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