三路归并排序Java代码
时间: 2023-12-18 07:26:45 浏览: 25
以下是三路归并排序的Java代码:
```
public class MergeSort {
public static void mergeSort(int[] arr, int left, int right) {
if (left >= right) {
return;
}
int mid1 = left + (right - left) / 3;
int mid2 = left + 2 * (right - left) / 3;
mergeSort(arr, left, mid1);
mergeSort(arr, mid1 + 1, mid2);
mergeSort(arr, mid2 + 1, right);
merge(arr, left, mid1, mid2, right);
}
public static void merge(int[] arr, int left, int mid1, int mid2, int right) {
int[] temp = new int[right - left + 1];
int i = left, j = mid1 + 1, k = mid2 + 1, index = 0;
while (i <= mid1 && j <= mid2 && k <= right) {
if (arr[i] <= arr[j] && arr[i] <= arr[k]) {
temp[index++] = arr[i++];
} else if (arr[j] <= arr[i] && arr[j] <= arr[k]) {
temp[index++] = arr[j++];
} else {
temp[index++] = arr[k++];
}
}
while (i <= mid1 && j <= mid2) {
if (arr[i] <= arr[j]) {
temp[index++] = arr[i++];
} else {
temp[index++] = arr[j++];
}
}
while (i <= mid1 && k <= right) {
if (arr[i] <= arr[k]) {
temp[index++] = arr[i++];
} else {
temp[index++] = arr[k++];
}
}
while (j <= mid2 && k <= right) {
if (arr[j] <= arr[k]) {
temp[index++] = arr[j++];
} else {
temp[index++] = arr[k++];
}
}
while (i <= mid1) {
temp[index++] = arr[i++];
}
while (j <= mid2) {
temp[index++] = arr[j++];
}
while (k <= right) {
temp[index++] = arr[k++];
}
for (int m = 0; m < temp.length; m++) {
arr[left + m] = temp[m];
}
}
}
```