Problem Description:
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"].
Well, I guess this problem aims at testing your ability to think throughly. The tricky part in this problem is to take all possible cases into consideration and unify them to give a succinct code.
The code is as follows.
1 class Solution { 2 public: 3 vector<string> findMissingRanges(vector<int>& nums, int lower, int upper) { 4 vector<string> ranges; 5 int pre = lower - 1, n = nums.size(); 6 for (int i = 0; i <= n; i++) { 7 int cur = (i == n) ? upper + 1 : nums[i]; 8 if (cur - pre >= 2) 9 ranges.push_back(missingRanges(pre + 1, cur - 1)); 10 pre = cur; 11 } 12 return ranges; 13 } 14 private: 15 string missingRanges(int low, int up) { 16 return (low == up) ? to_string(low) : to_string(low) + "->" + to_string(up); 17 } 18 };
