题目

我是编码的新手，现在我想得到两个数组的总和......实际上是所有元素的总和。我很感激你的帮助。

P.S.每个数组仅包含整数。输出也是一个数字。

测试用例：

import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

// TODO: Replace examples and use TDD development by writing your own tests

public class SolutionTest {
    @Test
    public void sampleTests() {
        assertEquals(21, Sum.arrayPlusArray(new int[]{1,2,3}, new int[]{4,5,6}));
        assertEquals(-21, Sum.arrayPlusArray(new int[]{-1,-2,-3}, new int[]{-4,-5,-6}));
        assertEquals(15, Sum.arrayPlusArray(new int[]{0,0,0}, new int[]{4,5,6}));
        assertEquals(2100, Sum.arrayPlusArray(new int[]{100,200,300}, new int[]{400,500,600}));
    }
}

解题

My

public class Sum {

  public static int arrayPlusArray(int[] arr1, int[] arr2) {
    int sum = 0;
    for (int i = 0; i<arr1.length; i++) {
      sum += arr1[i];
    }
    for (int i = 0; i<arr2.length; i++) {
      sum += arr2[i];
    }
    return sum;
  }

}

Other

import java.util.stream.*;

public class Sum {

  public static int arrayPlusArray(int[] arr1, int[] arr2) {
    return IntStream.of(arr1).sum() + IntStream.of(arr2).sum();
  }

}

public class Sum {

  public static int arrayPlusArray(int[] arr1, int[] arr2) {
    return sumArrayElements(arr1) + sumArrayElements(arr2);
  }
  
  private static int sumArrayElements(int[] arr) {
    int sum = 0;
    for (int i : arr) {
      sum += i;
    }
    return sum;
  }

}

后记

原来我还在想有没有库函数有类似这样的方法呢。