LeetCode 561. Array Partition I [Easy]
Problem: Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) for all i from 1 to n as large as possible. Example 1: Input: [1,4,3,2] Output: 4 Explanation: n is 2, and the maximum sum of pairs is 4 = min(1, 2) + min(3, 4). Note: n is a positive integer, which is in the range of [1, 10000..
2020. 8. 26.
LeetCode 42. Trapping Rain Water [Hard]
Problem: Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. The above elevation map is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. Thanks Marcos for contributing this image! Example: Input: [0,1,0,2,1,0,1,3,2,1,2,1] Output: ..
2020. 8. 24.
LeetCode 49. Group Anagrams
Problem: Given an array of strings, group anagrams together. Example: Input: ["eat", "tea", "tan", "ate", "nat", "bat"], Output: [ ["ate","eat","tea"], ["nat","tan"], ["bat"] ] Summary: 1. Create a defaultdict(list) to save the sorted word as a key in list format. 2. For each word, sort the word so that any anagram word would be saved in a list under same key. 3. return with all values saved in ..
2020. 8. 19.
