Summary Ranges

题目：

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"].

cpp：

class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        vector<string> result;
        if (nums.empty())
            return result;

        int start = nums[0];
        int end = nums[0];

        int len = nums.size();
        for (int i = 1; i < len; i++) {
            if ( nums[i] == nums[i - 1] || nums[i] == (nums[i-1]+1)) {
                end = nums[i];
            } else {
                result.push_back(format(start,end));
                start = nums[i];
                end = start;
            }
        }
        result.push_back(format(start,end));
        return result;
    }

//    string format(int begin,int end){
//        char buffer[32];
//        if(begin == end){
//            sprintf(buffer,"%d",begin);
//        }else{
//            sprintf(buffer,"%d->%d",begin,end);
//        }
//        return string(buffer);
//    }
    
    string format(int begin,int end){
        stringstream ss;
        if(begin == end){
            ss << begin;
        }else{
            ss << begin << "->" << end;
        }
        return ss.str();
    }
};

python：

class Solution(object):
    def summaryRanges(self, nums):
        x, size = 0, len(nums);
        result = []
        while x < size:
            c, r = x, str(nums[x])
            while x + 1 < size and nums[x + 1] == nums[x] + 1:
                x += 1
            if x > c:
                r += "->" + str(nums[x])
            result.append(r)
            x += 1
        return result;