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add 169 java, progress
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‎README.md‎

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119 | [Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)| [Python](./leetcode_python/Array/pascals-triangle-ii.py) | _O(n^2)_ | _O(1)_ | Easy |array, check with `# 118 Pascal's Triangle`, `amazon`| OK** (4)
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121 | [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)| [Python](./leetcode_python/Array/best-time-to-buy-and-sell-stock.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Array/BestTimeToBuyAndSellStock.java) | _O(n)_ | _O(1)_ | Easy |Curated Top 75, `dp`,`basic`,`greedy`,`UBER`, `M$`, `amazon`, `fb`| OK****** (7) (but again)
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157 | [Read N Characters Given Read4](https://leetcode.com/problems/read-n-characters-given-read4/) | [Python](./leetcode_python/Array/read-n-characters-given-read4.py) | _O(n)_ | _O(1)_ | Easy |🔒, buffer, `google`, `amazon`, `fb`| AGAIN**** (3)
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163 | [Missing Ranges](https://leetcode.com/problems/missing-ranges/)| [Python](./leetcode_python/Array/missing-ranges.py) | _O(n)_ | _O(1)_ | Medium| two pointer, 🔒, `google`, `amazon` | AGAIN******* (3)
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163 | [Missing Ranges](https://leetcode.com/problems/missing-ranges/)| [Python](./leetcode_python/Array/missing-ranges.py),
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[Java](./leetcode_java/src/main/java/LeetCodeJava/Array/MissingRanges.java) | _O(n)_ | _O(1)_ | Medium| two pointer, 🔒, `google`, `amazon` | OK******* (4)
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169 | [Majority Element](https://leetcode.com/problems/majority-element/) |[Python](./leetcode_python/Array/majority-element.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Array/MajorityElement.java) | _O(n)_ | _O(1)_ | Easy |`amazon`| OK*
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189 | [Rotate Array](https://leetcode.com/problems/rotate-array/) | [Python](./leetcode_python/Array/rotate-array.py) | _O(n)_ | _O(1)_ | Medium |array, k % len(nums), good basic, `amazon`| OK* (7) (but again)
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209 | [Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum/) | [Python](./leetcode_python/Array/minimum-size-subarray-sum.py) | _O(n)_ | _O(1)_ | Medium | good basic, sliding window, `Binary Search`, `trick`,`2 pointers`, `fb` | OK********** (5) (but again)

‎data/progress.md‎

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# Progress
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# 2024-10-20
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- https://github.com/yennanliu/CS_basics/blob/master/doc/Leetcode_company_frequency-master/Google%206months-%20LeetCode.pdf
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# 2024-10-19
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- https://github.com/yennanliu/CS_basics/blob/master/doc/Leetcode_company_frequency-master/Google%206months-%20LeetCode.pdf
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‎data/progress.txt‎

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20241020: 163
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20241019: 298,729
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20241018: 1146
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20241014: 737

‎data/to_review.txt‎

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2020-07-14 -> ['130', '066,271', '711,046,126,127']
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2020-07-13 -> ['346,686', '738', '063,064,120,0146']
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2020-07-12 -> ['210,261', '396', '675,297,138']
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2020-07-11 -> ['066,271', '163', '361,393,133,207', '482,127,102,107']
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2020-07-11 -> ['163', '066,271', '361,393,133,207', '482,127,102,107']
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2020-07-10 -> ['734,737', '388', '836,860,863']
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2020-07-09 -> ['066,271', '694']
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2020-07-08 -> ['066,271', '163', '646', '663']
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2020-07-08 -> ['163', '066,271', '646', '663']
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2020-07-07 -> ['066,271', '210,261', '298', '776', '661,662', '703,787,819']
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2020-07-06 -> ['130', '163', '361,393,133,207', '669,682,739,763']
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2020-07-06 -> ['163', '130', '361,393,133,207', '669,682,739,763']
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2020-07-05 -> ['163', '734,737', '346,686', '771,775', '701,450', '642,652,657']
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2020-07-04 -> ['163', '210,261', '640,645', '545,617,628']
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2020-07-03 -> ['361,393,133,207', '482,127,102,107', '762', '606,459']

‎leetcode_java/src/main/java/LeetCodeJava/Array/MissingRanges.java‎

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package LeetCodeJava.Array;
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// https://leetcode.com/problems/missing-ranges/description/
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// https://leetcode.ca/all/163.html
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import java.util.ArrayList;
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import java.util.List;
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/**
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* 163. Missing Ranges
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* Given a sorted integer array nums, where the range of elements are in the inclusive range [lower, upper], return its missing ranges.
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* <p>
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* Example:
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* <p>
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* Input: nums = [0, 1, 3, 50, 75], lower = 0 and upper = 99,
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* Output: ["2", "4->49", "51->74", "76->99"]
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* Difficulty:
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* Medium
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* Lock:
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* Prime
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* Company:
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* Amazon Facebook Google Oracle
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* Problem Solution
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*/
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public class MissingRanges {
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// V0
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// IDEA : ARRAY + BOUNDARY HANDLING (fix by gpt)
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public List<List<Integer>> findMissingRanges(int[] nums, int lower, int upper) {
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List<List<Integer>> res = new ArrayList<>();
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// Edge case: if nums is empty, return the whole range
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if (nums.length == 0) {
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addRange(res, lower, upper);
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return res;
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}
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// Check for missing range before the first element
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if (nums[0] > lower) {
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addRange(res, lower, nums[0] - 1);
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}
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// Find missing ranges between the numbers in nums
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for (int i = 1; i < nums.length; i++) {
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if (nums[i] > nums[i - 1] + 1) {
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addRange(res, nums[i - 1] + 1, nums[i] - 1);
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}
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}
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// Check for missing range after the last element
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if (nums[nums.length - 1] < upper) {
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addRange(res, nums[nums.length - 1] + 1, upper);
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}
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return res;
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}
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// Helper method to add the range to the result list
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private void addRange(List<List<Integer>> res, int start, int end) {
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List<Integer> range = new ArrayList<>();
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range.add(start);
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if (start != end) {
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range.add(end);
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}
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res.add(range);
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}
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// V1
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// https://leetcode.ca/2016-05-11-163-Missing-Ranges/
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// public List<List<Integer>> findMissingRanges_1(int[] nums, int lower, int upper) {
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// int n = nums.length;
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// if (n == 0) {
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// return List.of(List.of(lower, upper));
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// }
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// List<List<Integer>> ans = new ArrayList<>();
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// if (nums[0] > lower) {
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// ans.add(List.of(lower, nums[0] - 1));
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// }
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// for (int i = 1; i < n; ++i) {
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// if (nums[i] - nums[i - 1] > 1) {
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// ans.add(List.of(nums[i - 1] + 1, nums[i] - 1));
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// }
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// }
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// if (nums[n - 1] < upper) {
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// ans.add(List.of(nums[n - 1] + 1, upper));
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// }
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// return ans;
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// }
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// V2
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}

‎leetcode_java/src/main/java/dev/workspace5.java‎

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// }
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// }
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// LC 163
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// https://leetcode.ca/all/163.html
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// 3.51 pm - 4.20 pm
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/**
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* Given a sorted integer array nums, where the range of
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* elements are in the inclusive range [lower, upper],
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* return its missing ranges.
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*
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*
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* exp 1:
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* Input: nums = [0, 1, 3, 50, 75], lower = 0 and upper = 99,
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* Output: ["2", "4->49", "51->74", "76->99"]
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*
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* -> idea 1
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*
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* 0,1, [2] 3, [50], [75]
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*
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* -> "2", "4,49", "51,74", "76,99"
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*
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*
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* -> loop over elements, compare prev, and current element
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* -> if any missing, then collect, then add to result array
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* -> then finally check upper bound and last element
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* -> add to result accordingly if there is a missing element
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*/
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public List<List<Integer>> findMissingRanges(int[] nums, int lower, int upper) {
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if (nums.length == 0){
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return null;
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}
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/**
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* Input: nums = [0, 1, 3, 50, 75], lower = 0 and upper = 99,
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* Output: ["2", "4->49", "51->74", "76->99"]
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*
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* nums = [0, 1, 3, 50, 75] res = []
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* x
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* x res = []
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* x res = [[2]]
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* x res = [[2], [4,49]]
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* x res = [[2], [4,49], [51,74]]
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*
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* res = [[2], [4,49], [51,74], [76,99]]
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*/
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List<List<Integer>> res = new ArrayList<>();
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for (int i = 1; i < nums.length; i++){
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// case 1: nums = [1, 3]
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if (nums[i] == nums[i-1]+2){
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List<Integer> missingPeriod = new ArrayList<>();
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missingPeriod.add(nums[i-1]+1);
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res.add(missingPeriod);
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}
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// case 2 : nums = [3, 50]
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else if (nums[i] != nums[i-1]){
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List<Integer> missingPeriod = new ArrayList<>();
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missingPeriod.add(nums[i-1]+1);
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missingPeriod.add(nums[i]-1);
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res.add(missingPeriod);
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}
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}
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// finally, check last element and upper bound
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if (upper != nums[nums.length-1]){
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List<Integer> missingPeriod = new ArrayList<>();
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missingPeriod.add(nums[nums.length-1] + 1);
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missingPeriod.add(upper);
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res.add(missingPeriod);
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}
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return res;
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}
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17811852

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}
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