You are given an arraynumsthat consists of non-negative integers. Let us definerev(x)as the reverse of the non-negative integerx. For example,rev(123) = 321, andrev(120) = 21. A pair of indices(i, j)isniceif it
https://leetcode.com/problems/count-submatrices-with-equal-frequency-of-x-and-y/description/ 给出一个二维的字符矩阵grid,其中grid[i][j]为'X', 'Y' 或 '.' 。返回满足下列条件的子矩阵(submatrices)的个数。 包含grid[0][0] 子矩阵中'X'出现的次数等于'Y'出现的次数 至少包含一个'X' 例如grid...
828. Count Unique Characters of All Substrings of a Given String # 题目 # Let’s define a function countUniqueChars(s) that returns the number of unique characters on s, for example if s = "LEETCODE" then "L", "T","C","O","D" are the unique characters
In the row i, number of rectangles between column j and k(inclusive) and ends in row i, is equal to SUM(min(nums[j, .. idx])) where idx go from j to k. Expected solution is O(n^3). Similar Questions Count Submatrices With Equal Frequency of X and Y Medium Discussion (18) ...
技术标签: python leetcode题解Description A good meal is a meal that contains exactly two different food items with a sum of deliciousness equal to a power of two. You can pick any two different foods to make a good meal. Given an array of integers deliciousness where deliciousness[i] is ...
对于统计数字出现频率的题目,最直接的思路就是使用一个hashmap,但是使用hashmap需要用到O(n)的辅助存储空间;同时我们注意到数组中数值的范围是1到n,所以就很容易想到Leetcode中的一道题,First Missing Positive的解题思路:扫描数组,并且把A[i]放到A[A[i]-1]的位置上,但是由于我们需要记录每个数值出现的次数,仅...
3616-make-array-elements-equal-to-zero 3622-maximum-frequency-of-an-element-after-performing-operations-i 3627-find-minimum-time-to-reach-last-room-i 3628-find-minimum-time-to-reach-last-room-ii 3629-total-characters-in-string-after-transformations-i 3631-count-k-reducible-numbers-less-than-n...
0438-Find-All-Anagrams-in-a-String 0443-String-Compression 0447-Number-of-Boomerangs 0450-Delete-Node-in-a-BST 0451-Sort-Characters-By-Frequency 0454-4Sum-II 0455-Assign-Cookies 0458-Poor-Pigs 0470-Implement-Rand10-Using-Rand7 0473-Matchsticks-to-Square 0474-Ones-and-Zer...