如果索引i处子列表（如果有的话）是按升序排列，如何返回true

Question

如果索引i处的子列表（如果有的话）按升序排列（每个项小于或等于下一项），如何返回true；否则为假。这就是我到目前为止所做的。然而，我似乎无法通过考试

public static boolean isAscending(ArrayList<ArrayList<Integer>> list, int i) {

    ArrayList<Integer> data = list.get(i);
    for (i = 0; i < data.size() - 1; i++) {
        if (data.get(i) > data.get(i + 1)) {
            return false;
        }
    }
    return true;
}

@Test @Graded(description="IsAscendingBasic")
public void testIsAscendingBasic() {
    assertFalse(ListOfListService.isAscending(emptyList, 0));

    assertFalse(ListOfListService.isAscending(oneRow, 0));
    assertFalse(ListOfListService.isAscending(oneRow, 1));
    assertFalse(ListOfListService.isAscending(oneRow, -1));

    assertTrue(ListOfListService.isAscending(list2, 0));
    assertFalse(ListOfListService.isAscending(list2, 1));
    assertFalse(ListOfListService.isAscending(list2, 2));
    assertTrue(ListOfListService.isAscending(list2, 3));
    assertTrue(ListOfListService.isAscending(list2, 4));
    assertTrue(ListOfListService.isAscending(list2, 5));

    list2.get(4).set(1, 20); // 20, 20
    assertTrue(ListOfListService.isAscending(list2, 4));

    assertTrue(ListOfListService.isAscending(list1, 1));

    assertTrue(ListOfListService.isAscending(list3_emptySubLists, 0)); // empty sub-list is ascending
    assertFalse(ListOfListService.isAscending(list3_emptySubLists, 1));
    currentMethodName = new Throwable().getStackTrace()[0].getMethodName();
}

@Test @Graded(description="IsAscendingComprehensive")
public void testIsAscendingComprehensive() {
    testIsAscendingBasic();
    assertFalse(ListOfListService.isAscending(null, 0));

    assertFalse(ListOfListService.isAscending(list4_nullItems, 0));
    assertTrue(ListOfListService.isAscending(list4_nullItems, 2));
    assertFalse(ListOfListService.isAscending(list4_nullItems, 3));
    assertFalse(ListOfListService.isAscending(list4_nullItems, 5));
    currentMethodName = new Throwable().getStackTrace()[0].getMethodName();
}

Answer 1

正如所评论的那样，reusei变量会导致意外的输出。

您可以通过在循环作用域中定义一个新的int j变量来修复它：

public static boolean isAscending(ArrayList<ArrayList<Integer>> list, int i) {
    ArrayList<Integer> data = list.get(i);

    for (int j = 0; j < data.size() - 1; j++) {
        if (data.get(j) > data.get(j + 1)) {
            return false;
        }
    }

    return true;
}

作为附带说明，请考虑只获得您需要的参数：

public static boolean isAscending(List<Integer> list) {
    for (int j = 0; j < list.size() - 1; j++) {
        if (list.get(j) > list.get(j + 1)) {
            return false;
        }
    }
    return true;
}

boolean isAscending = isAscending(list.get(3));