题目

铃木是一名修道士，他登上大型楼梯到达修道院，作为仪式的一部分。有些日子他爬楼梯比其他人多，这取决于他早上必须训练的学生人数。他很好奇在接下来的20年里可能会攀爬多少楼梯，并且花了一年时间来记录他的日常进度。

一年中记录的所有楼梯的总和将用于估计他可能在20年内爬升的数量。

20_year_estimate = one_year_total * 20

您将收到以下数据结构，表示一年中登录的铃木楼梯。您将获得全年的所有数据，因此无论如何记录，问题都应该很容易解决。

stairs = [sunday,monday,tuesday,wednesday,thursday,friday,saturday]

确保您的解决方案考虑到楼梯阵列中的所有嵌套。

楼梯阵列中的每个工作日都是一个阵列。

sunday = [6737, 7244, 5776, 9826, 7057, 9247, 5842, 5484, 6543, 5153, 6832, 8274, 7148, 6152, 5940, 8040, 9174, 7555, 7682, 5252, 8793, 8837, 7320, 8478, 6063, 5751, 9716, 5085, 7315, 7859, 6628, 5425, 6331, 7097, 6249, 8381, 5936, 8496, 6934, 8347, 7036, 6421, 6510, 5821, 8602, 5312, 7836, 8032, 9871, 5990, 6309, 7825]

您的功能应该使用上面的公式返回爬楼梯的20年估计值。

测试用例：

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

public class KataTests 
{
    @Test
    public void stairsIn20_BasicTest1() {
        int[] sunday = {6737, 7244, 5776, 9826, 7057, 9247, 5842, 5484, 6543, 5153, 6832, 8274,
          7148, 6152, 5940, 8040, 9174, 7555, 7682, 5252, 8793, 8837, 7320, 8478, 6063, 
          5751, 9716, 5085, 7315, 7859, 6628, 5425, 6331, 7097, 6249, 8381, 5936, 8496, 
          6934, 8347, 7036, 6421, 6510, 5821, 8602, 5312, 7836, 8032, 9871, 5990, 6309, 7825};

        int[] monday = {9175, 7883, 7596, 8635, 9274, 9675, 5603, 6863, 6442, 9500, 7468, 9719,
          6648, 8180, 7944, 5190, 6209, 7175, 5984, 9737, 5548, 6803, 9254, 5932, 7360, 9221, 
          5702, 5252, 7041, 7287, 5185, 9139, 7187, 8855, 9310, 9105, 9769, 9679, 7842,
          7466, 7321, 6785, 8770, 8108, 7985, 5186, 9021, 9098, 6099, 5828, 7217, 9387};

        int[] tuesday = {8646, 6945, 6364, 9563, 5627, 5068, 9157, 9439, 5681, 8674, 6379, 8292,
           7552, 5370, 7579, 9851, 8520, 5881, 7138, 7890, 6016, 5630, 5985, 9758, 8415, 7313,
           7761, 9853, 7937, 9268, 7888, 6589, 9366, 9867, 5093, 6684, 8793, 8116, 8493, 
           5265, 5815, 7191, 9515, 7825, 9508, 6878, 7180, 8756, 5717, 7555, 9447, 7703};

        int[] wednesday = {6353, 9605, 5464, 9752, 9915, 7446, 9419, 6520, 7438, 6512, 7102, 
             5047, 6601, 8303, 9118, 5093, 8463, 7116, 7378, 9738, 9998, 7125, 6445, 6031, 8710,
             5182, 9142, 9415, 9710, 7342, 9425, 7927, 9030, 7742, 8394, 9652, 5783, 7698, 
             9492, 6973, 6531, 7698, 8994, 8058, 6406, 5738, 7500, 8357, 7378, 9598, 5405, 9493};

        int[] thursday = {6149, 6439, 9899, 5897, 8589, 7627, 6348, 9625, 9490, 5502, 5723, 8197,
            9866, 6609, 6308, 7163, 9726, 7222, 7549, 6203, 5876, 8836, 6442, 6752, 8695, 8402,
            9638, 9925, 5508, 8636, 5226, 9941, 8936, 5047, 6445, 8063, 6083, 7383, 7548, 5066, 
            7107, 6911, 9302, 5202, 7487, 5593, 8620, 8858, 5360, 6638, 8012, 8701};

        int[] friday = {5000, 5642, 9143, 7731, 8477, 8000, 7411, 8813, 8288, 5637, 6244, 6589, 6362, 
         6200, 6781, 8371, 7082, 5348, 8842, 9513, 5896, 6628, 8164, 8473, 5663, 9501, 
         9177, 8384, 8229, 8781, 9160, 6955, 9407, 7443, 8934, 8072, 8942, 6859, 5617,
         5078, 8910, 6732, 9848, 8951, 9407, 6699, 9842, 7455, 8720, 5725, 6960, 5127};

        int[] saturday = {5448, 8041, 6573, 8104, 6208, 5912, 7927, 8909, 7000, 5059, 6412, 6354, 8943, 
            5460, 9979, 5379, 8501, 6831, 7022, 7575, 5828, 5354, 5115, 9625, 7795, 7003, 
            5524, 9870, 6591, 8616, 5163, 6656, 8150, 8826, 6875, 5242, 9585, 9649, 9838, 
            7150, 6567, 8524, 7613, 7809, 5562, 7799, 7179, 5184, 7960, 9455, 5633, 9085};
        int[][] stairs = {sunday,monday,tuesday,wednesday,thursday,friday,saturday};  
        long expectedResult = 54636040;
        assertEquals(expectedResult, Kata.stairsIn20(stairs));
    }
}

解题

public class Kata
{
    public static long stairsIn20(int[][] stairs)
    {
       int sum = 0;
       for (int i = 0; i<stairs.length; i++) {
         for (int j = 0; j < stairs[i].length; j++) {
           sum = sum + stairs[i][j];
         }
       }
       return (long)(sum*20);
    }
}

Other

import java.util.Arrays;

public class Kata
{
    public static long stairsIn20(int[][] stairs)
    {
        return 20 * Arrays.stream(stairs).flatMapToInt(arr -> Arrays.stream(arr)).sum();
    }
}

后记

基础不扎实，练习过程中突然忘记强制转换的写法。。。