Problem 17 Number letter counts （统计字母）

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最新推荐文章于 2019-09-09 13:17:53 发布

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分类专栏： Project Euler ACM_暴力穷举 ACM_字符串文章标签： Problem 17 Number letter counts 统计字母

本文链接：https://blog.youkuaiyun.com/liangzhaoyang1/article/details/52944918

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本文介绍了一种计算从1到1000所有数字英文表达中字母总数的方法，并提供了完整的C++代码实现。文章通过分解数字范围（1-9, 10-19, 20-99, 100-999, 1000），分别计算各区间内数字的字母长度总和。

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Number letter counts

Problem 17

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 spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of "and" when writing out numbers is in compliance with British usage.

题解：从1算到100，再从100 算到1000.

代码：

#include <bits/stdc++.h>
using namespace std;
int main()
{
  //1-9
  int s1[] = { 0, 3, 3, 5, 4, 4, 3, 5, 5, 4 };
 //10-19
  int s2[] = { 3, 6, 6, 8, 8, 7, 7, 9, 8, 8 };
  //20 30 40 50 60 70 80 90
  int s3[] = { 0, 0, 6, 6, 5, 5, 5, 7, 6, 6 };

  int hundred = 7;
  int And = 3;
  int thousand = 8;

  int i;
  int sum = 0;
  
  //1-9
  for (i = 1; i < 10; i++)
  {
    sum += s1[i];
  }
  
  //10-19
  for (i = 0; i < 10; i++){
    sum += s2[i];
  }
  
 //20-99
  for (i = 20; i < 100; i++){
    sum += s3[i/10] + s1[i%10];
  }
  
 //100-999
  for (i = 1; i < 10; i++)
  {
    int j;
   //计算hundred 
    sum += s1[i] + hundred;
    // i*100 + j
    for (j = 1; j < 10; j++){
      sum += s1[i] + hundred + And + s1[j];
    }
    //i*100 + j*10 
    for (j = 0; j < 10; j++) {
      sum += s1[i] + hundred + And + s2[j];
    }
    //i*100 +j*10 +k
    for (j = 20; j < 100; j++) {
      sum += s1[i] + hundred + And + s3[j/10] + s1[j%10];
    }
  }
  
  //1000
  sum += 3 + thousand;
  
  cout<<sum<<endl;
  return 0;
}