LeetCode Q163: Missing Ranges

Given a sorted integer array where the range of elements are [lower, upper] inclusive, return its missing ranges.

For example, given [0, 1, 3, 50, 75], lower = 0 and upper = 99, return ["2", "4->49", "51->74", "76->99"].







	class Solution {
	public:
	vector<string> findMissingRanges(vector<int>& nums, int lower, int upper) {
	vector<string> res;
	if(nums.size()==0||nums[0]!=lower)
	nums.insert(nums.begin(), lower-1);
	if(nums[nums.size()-1]!=upper)
	nums.insert(nums.end(), upper+1);
	for(int p=0;p<nums.size()-1; p++){
	if(nums[p+1]-nums[p]>2){
	string s(to_string(nums[p]+1)+string("->")+to_string(nums[p+1]-1));
	res.push_back(s);
	}
	if(nums[p+1]-nums[p]==2){
	string s(to_string(nums[p]+1));
	res.push_back(s);
	}
	}
	return res;
	}
	};

view raw Q163.cpp hosted with ❤ by GitHub

Round 2 solution:

	class Solution {
	public:
	vector<string> findMissingRanges(vector<int>& nums, int lower, int upper) {
	vector<string> res;
	if(nums.size()==0||nums[0]!=lower)
	nums.insert(nums.begin(), lower-1);
	if(nums[nums.size()-1]!=upper)
	nums.insert(nums.end(), upper+1);
	for(int i=1; i<nums.size(); i++){
	int lb = nums[i-1]+1;
	int rb = nums[i]-1;
	if(lb==rb)
	res.push_back(to_string(lb));
	if(lb<rb)
	res.push_back(to_string(lb)+string("->")+to_string(rb));
	}
	return res;
	}
	};

view raw Q163Rnd2.cpp hosted with ❤ by GitHub