求出字符串中最长的数字串的长度

问题1

• 求出字符串中的最长连续数字串的长度

• 代码

  #include <iostream>
  #include <vector>
  #include <math.h>
  #include <random>
  #include <limits>
  #include <string>
  using namespace std;
  
  int main()
  {
      string str;
  
      cin >> str;
  
      int index = 0;
      int max_len = 0;
      int curr_len = 0;
      int max_start = 0;
      int curr_start = 0;
      while ( index < str.size() )
      {
          if (str[index] >= '0' && str[index] <= '9')
          {
              curr_start = index;
              index++;
              curr_len = 1;
              while (index < str.size() && str[index] >= '0' && str[index] <= '9')
              {
                  index++;
                  curr_len++;
              }
              if (max_len < curr_len)
              {
                  max_start = curr_start;
                  max_len = curr_len;
              }
          }
          else
              index++;
      }
      cout << "max len : " << max_len << endl;
      cout << "max start : " << max_start << endl;
  
      system("pause");
      return 0;
  }
  

问题2

• 描述：数字串之间允许最多有一个非数字的字符，计算此时求得的最长数字串。(比如说1234a12的结果是7)。

• 代码

  #include <iostream>
  #include <vector>
  #include <math.h>
  #include <random>
  #include <limits>
  #include <string>
  #include <math.h>
  #include <algorithm>
  using namespace std;
  
  int main()
  {
      string str;
  
      cin >> str;
  
      int non_digit_len = 0;
  
      int index = 0;
      int curr_len = 0;
      int max_start = 0;
      int max_len = 0;
      int last_len = -1;
      while ( index < str.size() )
      {
          if (str[index] >= '0' && str[index] <= '9')
          {
              while (index < str.size() && str[index] >= '0' && str[index] <= '9')
              {
                  index++;
                  curr_len++;
              }
              if (max_len < curr_len + last_len + 1)
              {
                  max_len = curr_len;
              }
          }
          else
          {
              while (index < str.size() && !(str[index] >= '0' && str[index] <= '9'))
              {
                  index++;
                  non_digit_len++;
              }
              if (non_digit_len == 1)
              {
                  last_len = curr_len;
                  curr_len = 0;
              }
              else
              {
                  last_len = -1;
                  curr_len = 0;
              }
              non_digit_len = 0;
          }
          max_len = std::max(max_len, curr_len + last_len + 1);
      }
  
      cout << "max len : " << max_len << endl;
  
      system("pause");
      return 0;
  }