leetcode-【中等题】228. Summary Ranges

题目：

228. Summary Ranges

Given a sorted integer array without duplicates, return the summary of its ranges.

For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].

答案：

就是找连续的序列。

直接判断相邻数据大小是否相差为1即可，主要是注意最后的数字要特殊考虑一下。

链接：

https://leetcode.com/problems/summary-ranges/

代码：

 #include <vector>
 #include <string>
 #include <sstream>

 using std::vector;
 using std::string;
 using std::ostringstream;

 class Solution {
 private:
     string num2str(int& num)
     {
         ostringstream stream;
         stream << num;
         return stream.str();
     }

 public:
     vector<string> summaryRanges(vector<int>& nums) {
         unsigned int len = nums.size();
         unsigned int index,inIndex;
         unsigned int minIndex = ;
         unsigned int maxIndex = ;

         vector<string> ans;
         if(len == )
         {
             return ans;
         }

         if(len == )
         {
             ans.push_back(num2str(nums[]));
             return ans;
         }

         for(index = ; index < len - ; ++ index)
         {
             if(nums[index] +  == nums[index + ])
             {
                 maxIndex = index + ;
             }else
             {
                 string tmp = "";
                 tmp += num2str(nums[minIndex]);
                 if(maxIndex > minIndex)
                 {
                     tmp += "->";
                     tmp += num2str(nums[maxIndex]);
                 }
                 ans.push_back(tmp);

                 minIndex = index + ;
                 maxIndex = index + ;
             }
         }

         if(nums[len-] +  == nums[len - ])
         {
             maxIndex = len - ;
         }else
         {
             minIndex = len - ;
             maxIndex = len - ;
         }

         string tmp = "";
         tmp += num2str(nums[minIndex]);
         if(maxIndex > minIndex)
         {
             tmp += "->";
             tmp += num2str(nums[maxIndex]);
         }
         ans.push_back(tmp);

         return ans;
     }
 };