我使用Java创建了一个类来解决这个问题,下面也展示了代码。
解决方案:
package com.conorgriffin.flattener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class IntegerArrayFlattener {
public static Integer[] flatten(Object[] inputArray) throws IllegalArgumentException {
if (inputArray == null) return null;
List<Integer> flatList = new ArrayList<Integer>();
for (Object element : inputArray) {
if (element instanceof Integer) {
flatList.add((Integer) element);
} else if (element instanceof Object[]) {
flatList.addAll(Arrays.asList(flatten((Object[]) element)));
} else {
throw new IllegalArgumentException("Input must be an array of Integers or nested arrays of Integers");
}
}
return flatList.toArray(new Integer[flatList.size()]);
}
}
单元测试:
package com.conorgriffin.flattener;
import org.junit.Assert;
import org.junit.Test;
public class IntegerArrayFlattenerTest {
Integer[] expectedArray = new Integer[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
@Test
public void testNullReturnsNull() throws IllegalArgumentException {
Assert.assertNull(
"Testing a null argument",
IntegerArrayFlattener.flatten(null)
);
}
@Test
public void testEmptyArray() throws IllegalArgumentException {
Assert.assertArrayEquals(
"Testing an empty array",
new Integer[]{},
IntegerArrayFlattener.flatten(new Object[]{})
);
}
@Test
public void testFlatArray() throws IllegalArgumentException {
Assert.assertArrayEquals(
"Testing a flat array",
expectedArray,
IntegerArrayFlattener.flatten(new Object[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
);
}
@Test
public void testNestedArray() throws IllegalArgumentException {
Assert.assertArrayEquals(
"Testing nested array",
expectedArray,
IntegerArrayFlattener.flatten(new Object[]{1, 2, 3, 4, new Object[]{5, 6, 7, 8}, 9, 10})
);
}
@Test
public void testMultipleNestedArrays() throws IllegalArgumentException {
Assert.assertArrayEquals(
"Testing multiple nested arrays",
expectedArray,
IntegerArrayFlattener.flatten(new Object[]{1, 2, new Object[]{3, 4, new Object[]{5}, 6, 7}, 8, 9, 10})
);
}
@Test(expected = IllegalArgumentException.class)
public void throwsExceptionForObjectInArray() throws IllegalArgumentException {
IntegerArrayFlattener.flatten(
new Object[]{new Object()}
);
}
@Test(expected = IllegalArgumentException.class)
public void throwsExceptionForObjectInNestedArray() throws IllegalArgumentException {
IntegerArrayFlattener.flatten(
new Object[]{1, 2, new Object[]{3, new Object()}}
);
}
@Test(expected = IllegalArgumentException.class)
public void throwsExceptionForNullInArray() throws IllegalArgumentException {
IntegerArrayFlattener.flatten(
new Object[]{null}
);
}
@Test(expected = IllegalArgumentException.class)
public void throwsExceptionForNullInNestedArray() throws IllegalArgumentException {
IntegerArrayFlattener.flatten(
new Object[]{1, 2, new Object[]{3, null}}
);
}
}