@@ -0,0 +1,854 @@
+import org.junit.Test;%0A%0Aimport static org.assertj.core.api.Assertions.assertThat;%0A%0Apublic class SuperSimpleSumOfMatrixDiagonals %7B%0A%0A    /*%0A     find the sum of the two diagonals and output the absolute value of the difference%0A     Input:%0A       %5B %5B1, 2, 3%5D, %5B4, 5, 6%5D, %5B7, 8, 9%5D %5D%0A     Output:%0A       abs((1+5+9)-(3+5+7))%0A     */%0A    @Test%0A    public void superSimpleSumOfMatrixDiagonals_Test() %7B%0A        int sumOfDiagonal1 = 0, sumOfDiagonal2 = 0;%0A%0A        int%5B%5D%5B%5D array = %7B%0A                %7B1, 2, 3%7D,%0A                %7B4, 5, 6%7D,%0A                %7B7, 8, 9%7D%0A        %7D;%0A%0A        for (int i = 0, j = array.length -1; i %3C array.length; i++, j--) %7B%0A            sumOfDiagonal1 += array%5Bi%5D%5Bi%5D;%0A            sumOfDiagonal2 += array%5Bi%5D%5Bj%5D;%0A        %7D%0A%0A%0A        int result = Math.abs(sumOfDiagonal1 - sumOfDiagonal2);%0A%0A        assertThat(result).isEqualTo(0);%0A    %7D%0A%7D%0A

add simple "sum of matrix diagonals" test