算法 数组中出现次数最多的数字 MD

public class Test { public static void main(String[] args) throws Exception {
int[] array = { 1, 1, 1, 1, 5, 1, 5, 1, 5, 5, 5 };
qsort(array);
System.out.println(Arrays.toString(array));
} public static void qsort(int[] arr) {
qsort(arr, 0, arr.length - 1);
} public static void qsort(int[] arr, int low, int high) {
if (low < high) {
int pivot = partition(arr, low, high);//将表一分为二
qsort(arr, low, pivot);//对低子表【递归】排序
qsort(arr, pivot + 1, high);//递归对高子表递归排序
}
} private static int partition(int[] arr, int low, int high) {
int pivotkey = arr[low];//选择一个【基准元素】，通常选择第一个元素或者最后一个元素
while (low < high) {//从表的两端【交替】地向中间扫描
//将比基准元素小的交换到低端
while (low < high && arr[high] >= pivotkey) {
high--;
}
swap(arr, low, high);
//将比基准元素大的交换到高端
while (low < high && arr[low] <= pivotkey) {
low++;
}
swap(arr, low, high);
}
return low;//此时基准元素在其排好序后的正确位置
} public static void swap(int[] arr, int i, int j) {
if (i == j) return;
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}

public class Test { public static void main(String[] args) throws Exception {
int[] array = { 1, 1, 1, 1, 5, 1, 5, 1, 5, 5, 5 };
System.out.println(mostNum(array));
} public static int mostNum(int[] array) {
HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
for (int i = 0; i < array.length; i++) {
int key = array[i];
if (map.containsKey(key)) {
map.replace(key, map.get(key) + 1);
} else {
map.put(key, 1);
}
} int key = array[0];
for (Entry<Integer, Integer> entry : map.entrySet()) {
if (entry.getValue() > map.get(key)) {
key = entry.getKey();
}
}
return key;
}
}

public class Test { public static void main(String[] args) throws Exception {
int[] array = { 1, 1, 1, 1, 5, 1, 5, 1, 5, 5, 5 };
System.out.println(mostNum(array));
} public static int mostNum(int[] array) {
int count = 1, value = array[0]; for (int i = 1; i < array.length; i++) {
if (array[i] == value) {
count++; //如果下一个数字与之前保存的数字相同，则次数加1
} else {
count--; //如果不同，则次数减1
}
if (count == 0) {
value = array[i]; //如果次数为0，则需要保存下一个数字，并把次数设定为1
count = 1;
}
}
return value;
}
}