Leetcode 228. Summary Ranges

228. Summary Ranges

Total Accepted: 51769
Total Submissions: 203058
Difficulty: Medium

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"].

思路：见代码。

注意c++中数字转换为string可以用to_string()函数。

实现string和int的相互转换可以用stringstream。

代码：

用to_string()函数：

 1 class Solution {
 2 public:
 3     vector<string> summaryRanges(vector<int>& nums) {
 4         int low=0,high=0,n=nums.size(),i;
 5         vector<string> res;
 6         string lows,highs;
 7         while(high<n){
 8             lows=to_string(nums[low]);
 9             i=0;
10             while(high<n&&nums[low]+i==nums[high]){
11                 i++;
12                 high++;
13             }
14             if(i>1){
15                 highs=to_string(nums[high-1]);
16                 lows=lows+"->"+highs;
17             }
18             res.push_back(lows);
19             low=high;
20         }
21         return res;
22     }
23 };

用stringstream：如果想通过使用同一stringstream对象实现多种类型的转换，请注意在每一次转换之后都必须调用clear()成员函数

 1 class Solution {
 2 public:
 3     vector<string> summaryRanges(vector<int>& nums) {
 4         int low=0,high=0,n=nums.size(),i;
 5         vector<string> res;
 6         stringstream ss;
 7         string lows,highs;
 8         while(high<n){
 9             ss<<nums[low];
10             ss>>lows;
11             ss.clear();
12             i=0;
13             while(high<n&&nums[low]+i==nums[high]){
14                 i++;
15                 high++;
16             }
17             if(i>1){
18                 ss<<nums[high-1];
19                 ss>>highs;
20                 ss.clear();
21                 lows=lows+"->"+highs;
22             }
23             res.push_back(lows);
24             low=high;
25         }
26         return res;
27     }
28 };