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摘要： 题意大概是： 一个数比如242，把所有数字分成两组，而且两组的和相等，那么这个数就是神奇数，此时242，能够分成{2,2}和{4}，所以242是神奇数。 题目要求输入n和m求[n,m]区间内神奇数的个数。 思路： 对于任意一个数字，将每一位上的数字保存到数组里，并求所有位上的数字的和sum。然后使用 阅读全文

摘要： Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the hist 阅读全文

摘要： Given a non-negative integer, you could swap two digits at most once to get the maximum valued number. Return the maximum valued number you could get. 阅读全文

摘要： Given a binary search tree and the lowest and highest boundaries as L and R, trim the tree so that all its elements lies in [L, R] (R >= L). You might 阅读全文

摘要： Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. 阅读全文

摘要： Given two integers n and k, you need to construct a list which contains n different positive integers ranging from 1 to n and obeys the following requ 阅读全文

摘要： 题意大概是给定M×N的棋盘格，从左上到右下，只能向右或者向下走，每走一步需要加上棋盘格子内的数值(有正有负)。 需要随时保证当前的数值>=1。问初始需要最少的值是多少？ 思路： 动态规划。用dp[i][j]代表当前最大的数值。首先求出dp[m][n],得出到达右下角的最优值。 然后再回溯求出从左上角 阅读全文

摘要： If the depth of a tree is smaller than 5, then this tree can be represented by a list of three-digits integers. For each integer in this list: Given a 阅读全文

摘要： Given an array with n integers, your task is to check if it could become non-decreasing by modifying at most 1 element. We define an array is non-decr 阅读全文

摘要： Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For exam 阅读全文