No.242 - LeetCode[228] Summary Ranges

/*
 * @lc app=leetcode id=228 lang=cpp
 *
 * [228] Summary Ranges
 */

// @lc code=start
class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        int N = nums.size();
        vector<string> ans;
        if(N <= 0) return ans;
        int start = nums[0];
        int cnt = 0;
        for(int i=1;i<N;i++){
            if(nums[i] == nums[i-1]+1){
                cnt++;
                continue;
            }
            addStr(ans,start,start+cnt);
            start = nums[i];
            cnt = 0;
        }
        addStr(ans,start,start+cnt);
        return ans;
    }
    void addStr(vector<string>& ans,int a,int b){
        if(a == b){
            ans.push_back(to_string(a));
            return ;
        } 
        ans.push_back(to_string(a) + "->" + to_string(b));
    }
};
// @lc code=end