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[OJ.leetcode] combinations https://oj.leetcode.com/problems/combinations/ Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example, If n = 4 and k = 2, a solution is:[ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] /* 시간/공간 복잡도 : O(nCk) nCk = (n!/k!(n-k)!)? 시간 복잡도 계산이 은근히 복잡하다. n회 루프 중 현재 원소의 갯수 n이 < k 일때까지 계속해서 재귀호출을 하므로..으 순열/조합 을 한번에 짜는게 의외로 잘 안된다. 이번에도 대여섯번 컴파일러에 의존해서 버그 수정 후 .. 더보기
[OJ.leetcode] sort-colors https://oj.leetcode.com/problems/sort-colors/ Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively. Note: You are not suppose to use the library's sort function for this problem. click to show follow up.Follow up: A rather straight forward solution is a two-pass algorithm using counting sort. First, iterate the array counting number of 0's, 1's, and.. 더보기
[OJ.leetcode] substring-with-concatenation-of-all-words https://oj.leetcode.com/problems/substring-with-concatenation-of-all-words/ You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concatenation of each word in L exactly once and without any intervening characters. For example, given: S: "barfoothefoobarman" L: ["foo", "bar"] You should return the indices: [0,.. 더보기

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