Author: huafu

27 Dec

Posted at 18:29h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Each row must contain the digits 1-9 without repetition. Each column must contain the digits 1-9 without repetition. Each of the nine 3 x 3 sub-boxes of the grid must contain...

27 Dec

Posted at 17:12h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not found in the array, return [-1, -1]. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [5,7,7,8,8,10], target = 8 Output: [3,4] Example...

27 Dec

Posted at 16:46h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] There is an integer array nums sorted in ascending order (with distinct values). Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k < nums.length) such that the resulting array is [nums[k], nums[k+1], ...

27 Dec

Posted at 15:51h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator. The integer division should truncate toward zero, which means losing its fractional part. For example, 8.345 would be truncated to 8, and -2.7335 would be truncated to -2. Return the quotient after dividing dividend by divisor. Note: Assume we are dealing with an...

27 Dec

Posted at 15:25h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "sadbutsad", needle = "sad" Output: 0 Explanation: "sad" occurs at index 0 and 6. The first occurrence is at index 0, so we...

26 Dec

Posted at 22:57h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.) Example 1: Input: head = [1,2,3,4] Output: [2,1,4,3] Example 2: Input: head...

26 Dec

Posted at 22:24h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Given the head of a linked list, remove the nth node from the end of the list and return its head. Example 1: Input: head = [1,2,3,4,5], n = 2 Output: [1,2,3,5] Example 2: Input: head = [1], n = 1 Output: [] Example 3: Input: head = [1,2], n...

26 Dec

Posted at 22:13h in Coding by
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Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. A mapping of digits to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters. Example 1: Input:...

26 Dec

Posted at 22:06h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text]Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. Notice that the solution set must not contain duplicate triplets. Example 1: Input: nums =...

26 Dec

Posted at 22:05h in Coding by
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[vc_row css_animation="" row_type="row" use_row_as_full_screen_section="no" type="full_width" angled_section="no" text_align="left" background_image_as_pattern="without_pattern"][vc_column][vc_column_text] Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V ...