Summary Ranges(leetcode 228)

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”].

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class Solution {public:    vector<string> summaryRanges(vector<int>& nums) {        vector<string> a;        if (nums.size() == 0) {            return a;        }        int begin = nums[0];        char buff[100];        for (int i = 1; i <= nums.size(); ++i) {            if (i < nums.size() && nums[i] - nums[i - 1] == 1) {                continue;            } else {                if (nums[i - 1] == begin) {                    snprintf(buff, 100, "%d", begin);                    a.push_back(string(buff));                } else {                    snprintf(buff, 100, "%d->%d", begin, nums[i - 1]);                    a.push_back(string(buff));                }                begin = nums[i];            }        }        return a;    }};