알고리즘 트레이닝

문제 Given a sorted linked list, delete all duplicates such that each element appear only once. Example 1: Input: 1->1->2 Output: 1->2Example 2: Input: 1->1->2->3->3 Output: 1->2->3풀이 정렬된 단일연결리스트를 순회하며 중복(동일값) 여부를 확인하여 제거한다. class Solution: def deleteDuplicates(self, head: ListNode) -> ListNode: cur = head while cur : if cur.next and cur.val == cur.next.val : cur.next = cur.next.next else : cur = ..

문제 You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Note: Given n will be a positive integer. Example 1: Input: 2 Output: 2 Explanation: There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 stepsExample 2: Input: 3 Output: 3 Explanation: There are three ways to climb to..

문제 Implement int sqrt(int x). Compute and return the square root of x, where x is guaranteed to be a non-negative integer. Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned. Example 1: Input: 4 Output: 2Example 2: Input: 8 Output: 2 Explanation: The square root of 8 is 2.82842..., and since the decimal part is truncated, 2 i..

문제 Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word (last word means the last appearing word if we loop from left to right) in the string. If the last word does not exist, return 0. Note: A word is defined as a maximal substring consisting of non-space characters only. Example: Input: "Hello World" Output: 5풀이 class So..

문제 Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume no duplicates in the array. Example 1: Input: [1,3,5,6], 5 Output: 2Example 2: Input: [1,3,5,6], 2 Output: 1Example 3: Input: [1,3,5,6], 7 Output: 4Example 4: Input: [1,3,5,6], 0 Output: 0풀이 class Solution: def searchInsert(s..

문제 Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2Example 2: Input: haystack = "aaaaa", needle = "bba" Output: -1Clarification: What should we return when needle is an empty string? This is a great question to ask during an interview. For the purpose of this ..

문제 Given an array nums and a value val, remove all instances of that value in-place and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. The order of elements can be changed. It doesn't matter what you leave beyond the new length. Example 1: Given nums = [3,2,2,3], val = 3, Your function shoul..

문제 Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. Example 1: Given nums = [1,1,2], Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It does..