2013年5月27日

摘要： 将1……n的数表示成英文，求表示成这些英文的字母的和If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?NOTE:Do not count sp 阅读全文

摘要： 求2的1000次方的各个位置上的数的和215= 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.What is the sum of the digits of the number 21000?思想：普通算法肯定满足不了，只好自己实现大数算法，java的bigInteger应该可以做到这个吧，不过还是自己实现……构造一个334大的int数组，每一位存储最后计算结果的一个数值。只定义334个大小的数组的原因是因为在2的n次方最小最多3次就必须进一位，那么一位数最多可以保存2的三次方，所以取1000/3+1代码：private 阅读全文

摘要： 求格子的路径个数：Starting in the top left corner of a 22 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.How many such routes are there through a 2020 grid?思想：这是做了这么久之后我比较喜欢的一个题，终于要思考推一下下了。给格子上的顶点依次从(0,0)标起，往右或者往下两个数字依次加1，将题目的示例就可以转化为(0,0)->( 阅读全文