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Sort a linked list using insertion sort. 复杂度 o（n^2）; 插入排序 (Insertion Sort) 设有一组关键字｛K1， K2，…， Kn｝；排序开始就认为 K1 是一个有序序列；让 K2 插入上述表长为 1 的有序序列，使之成为一个表长为 2 的 阅读全文
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Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j]and the d 阅读全文
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Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is symmet 阅读全文
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Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical a 阅读全文
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import java.util.*; class Node{ String val; Set children = new HashSet(); // at most 15 children; public Node(String val){ this.val = val; this.children = new HashSet(); ... 阅读全文
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Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set. get(key) - Get the 阅读全文
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Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. 阅读全文
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You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you nee 阅读全文
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Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 1, 2, 3, 4, 5, 阅读全文
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A message containing letters from A-Z is being encoded to numbers using the following mapping: Given an encoded message containing digits, determine t 阅读全文