分治排序(java)

public class DivideSort {
    
    public static void divide(int[] arr, int start, int split, int end) {
        System.out.printf("分解:");
        for (int i = start; i <= end; i++) {
            if (i == split) {
                System.out.printf("(%d)t", arr[i]);
            } else {
                System.out.printf("%dt", arr[i]);
            }
        }
        System.out.println();
        if (split - start > 1) {
            divide(arr, start, (start + split) / 2, split);
        } else {
            if (arr[start] > arr[split]) {
                conquer(arr, start, split);
            }
        }
        if (end - split > 1) {
            divide(arr, split, (end + split) / 2, end);
        } else {
            if (arr[split] > arr[end]) {
                conquer(arr, split, end);
            }
        }
        combine(arr, start, split, end);
    }

    
    public static void conquer(int[] arr, int start, int end) {
        System.out.printf("start:%d,end:%dn", start, end);
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
        for (int i : arr) {
            System.out.printf("%dt", i);
        }
        System.out.println();
        System.out.println("==================");
    }

    
    public static void combine(int[] arr, int start, int split, int end) {
        System.out.printf("合并:start:%d,split:%d,end%dn", start, split, end);
        int[] temp = new int[end - start + 1];
        int index = 0;
        int left = start;
        int right = split;
        while (left < split || right <= end) {
            if (left >= split) {
                temp[index] = arr[right];
                right++;
            } else if (right > end) {
                temp[index] = arr[left];
                left++;
            } else if (arr[left] > arr[right]) {
                temp[index] = arr[right];
                right++;
            } else {
                temp[index] = arr[left];
                left++;
            }
            index++;
        }
        if (temp.length >= 0) {
            System.arraycopy(temp, 0, arr, start, temp.length);
        }
        System.out.print("合并后:t");
        for (int i : arr) {
            System.out.printf("%dt", i);
        }
        System.out.println();
    }
    public static void  sort(int[] arr) {
        divide(arr, 0, (arr.length - 1) / 2, arr.length - 1);
    }

    public static void main(String[] args) {
        // 生成多少个数字
        int size = 1000;
        // 多少个数换行
        int linefeed=100;
        int[] arr = new int[size];
        for (int i = 0; i < size; i++) {
            arr[i] = (int) (Math.random() * size);
        }
        long startTime = System.currentTimeMillis();
        System.out.println("排序前:");
        for (int i = 0; i < arr.length; i++) {
            System.out.printf("%dt", arr[i]);
            if ((i + 1) % linefeed == 0) {
                System.out.println();
            }
        }
        sort(arr);
        long endTime = System.currentTimeMillis();
        System.out.println("排序耗时(毫秒):" + (endTime - startTime));
        System.out.println("排序后:");
        for (int i = 0; i < arr.length; i++) {
            System.out.printf("%dt", arr[i]);
            if ((i + 1) % linefeed == 0) {
                System.out.println();
            }
        }
    }
}