A decimal number is called deci-binary if each of its digits is either 0 or 1 without any leading zeros. For example, 101 and 1100 are deci-binary, while 112 and 3001 are not. Given a string n that represents a positive decimal integer, return the minimum number of positive deci-binary numbers needed so that they sum up to n.......
Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, and /. Each operand may be an integer or another expression. Note that division between two integers should truncate toward zero. It is guaranteed that the given RPN expression is always valid. That means the expression would always evaluate to a result, and there will not be any division by zero operation.......
Design a special dictionary with some words that searchs the words in it by a prefix and a suffix.......
Given a list of words, each word consists of English lowercase letters. Let’s say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make it equal to word2. For example, “abc” is a predecessor of “abac”. A word chain is a sequence of words [word_1, word_2, …, word_k] with k >= 1, where word_1 is a predecessor of word_2, word_2 is a predecessor of word_3, and so on. Return the longest possible length of a word chain with words chosen from the given list of words.......
Sparse Table是用于高效查询数组中指定范围极值的一种数据结构，一种典型的空间换时间的做法。......
Given an array of integers target. From a starting array, A consisting of all 1’s, you may perform the following procedure, let x be the sum of all elements currently in your array. choose index i, such that 0 <= i < target.size and set the value of A at index i to x. You may repeat this procedure as many times as needed. Return True if it is possible to construct the target array from A otherwise return False.......