LeetCode -Reverse Pairs】的更多相关文章

my solution: class Solution { public: int reversePairs(vector<int>& nums) { int length=nums.size(); ; ;i<length;i++) { ;j<length;j++) { if(nums[i]>2*nums[j]) count++; } } return count; } }; wrong answer : because   2147483647*2 is -2 (i…
Reverse Pairs 翻转对 题意 计算数组里面下标i小于j,但是i的值要大于j的值的两倍的搭配的个数(也就是可能会有多种搭配):网址 做法 这道题显然是不允许使用最简单的方法:两次循环,逐次进行判断,这样做的时间复杂度就是O(n^2),OJ无法通过,需要考虑另外的实现方式: class Solution(object): def reversePairs(self, nums): """ :type nums: List[int] :rtype: int "…
Given an array nums, we call (i, j) an important reverse pair if i < j and nums[i] > 2*nums[j]. You need to return the number of important reverse pairs in the given array. Example1: Input: [1,3,2,3,1] Output: 2 Example2: Input: [2,4,3,5,1] Output:…
For an array A, if i < j, and A [i] > A [j], called (A [i], A [j]) is a reverse pair.return total of reverse pairs in A. ExampleGiven A = [2, 4, 1, 3, 5] , (2, 1), (4, 1), (4, 3) are reverse pairs. return 3 这道题跟LeetCode上的那道Count of Smaller Numbers A…
Given an array nums, we call (i, j) an important reverse pair if i < j and nums[i] > 2*nums[j]. You need to return the number of important reverse pairs in the given array. Example1: Input: [1,3,2,3,1] Output: 2  Example2: Input: [2,4,3,5,1] Output:…
For an array A, if i < j, and A [i] > A [j], called (A [i], A [j]) is a reverse pair.return total of reverse pairs in A.   Example Given A = [2, 4, 1, 3, 5] , (2, 1), (4, 1), (4, 3) are reverse pairs. return 3 分析: 如果用两个for loop,非常简单. public class So…
LeetCode: Reverse Words in a String:Evaluate Reverse Polish Notation Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each operand may be an integer or another expression. Some examples: ["2&q…
leetcode:Reverse Bits 本题目收获 移位(<<  >>), 或(|),与(&)计算的妙用 题目: Reverse bits of a given 32 bits unsigned integer.For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in bin…
LeetCode--Reverse String Question Write a function that takes a string as input and returns the string reversed. Example: Given s = "hello", return "olleh". Answer class Solution { public: string reverseString(string s) { string str(s.…
Given an array nums, we call (i, j) an important reverse pair if i < j and nums[i] > 2*nums[j]. You need to return the number of important reverse pairs in the given array. Example1: Input: [1,3,2,3,1] Output: 2 Example2: Input: [2,4,3,5,1] Output:…
leetcode 493跟经典的逆序对问题没有什么区别, 首先考虑对数组前半部和后半部求逆序对数,若能保证两段数组都有序,则显然可以在线性时间内求出对数. 所以我们采用归并排序的方法,一方面让数组有序,另一方面计算子数组的逆序对数. 代码实现有些细节要注意,在比较时需要把Int转换为longlongint 不然会出错. class Solution { public: int reversePairs(vector<int>& nums) { int ans=0; if(nums.si…
题目如下: 解题思路:本题要求的是数组每个元素和所有排在这个元素后面的元素的值的二倍做比较.我们可以先把数组所有元素的二倍都算出来,存入一个新的数组newlist,并按升序排好.而后遍历nums数组的每个元素i,通过二分查找的方法在newlist中找到值比i小的元素中下标最大的那个(记为inx),那么符合条件i元素的reverse paris就是inx,累计所有的inx即可得到结果. 代码如下: class Solution(object): def reversePairs(self, num…
题意:给定一个数组nums,求若 i<j and nums[i] > 2*nums[j] 的逆序对. Note: 数组的长度不会超过50,000 不愧是hard模式的题目,虽然已经知道可以用归并排序来做,但是写出来的答案总有问题,真的是暴风哭泣 :( 一直在找bug,最后发现是我写的merge函数有问题,分析一下: 这是我一开始写的错误的merge函数,我是在 aux[i] > aux[j] 里面加入了若也满足 aux[i] > 2*aux[j] 来计算res int merge(…
Given a list of unique words. Find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1:Given words = ["bat", "tab", "cat"]Ret…
Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is. You may not alter the values in the nodes, only nod…
Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] is a palindrome. Example 1: Given words = ["bat", "tab", "cat"] R…
Write a function that takes a string as input and reverse only the vowels of a string. Example 1:Given s = "hello", return "holle". Example 2:Given s = "leetcode", return "leotcede". 这道题让我们翻转字符串中的元音字母,元音字母有五个a,e,i,o…
Write a function that takes a string as input and returns the string reversed. Example: Given s = "hello", return "olleh". 这道题没什么难度,直接从两头往中间走,同时交换两边的字符即可,参见代码如下: 解法一: class Solution { public: string reverseString(string s) { , right =…
Reverse a singly linked list. click to show more hints. Hint: A linked list can be reversed either iteratively or recursively. Could you implement both? 之前做到Reverse Linked List II 倒置链表之二的时候我还纳闷怎么只有二没有一呢,原来真是忘了啊,现在才加上,这道题跟之前那道比起来简单不少,题目为了增加些许难度,让我们分别用…
Reverse bits of a given 32 bits unsigned integer. For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000). Follow up:If this function i…
Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters.The input string does not contain leading or trailing spaces and the words are always separated by a single space.For example,Given s = "t…
Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the". Update (2015-02-12): For C programmers: Try to solve it in-place in O(1) space. click to show clarification. Cl…
Reverse a linked list from position m to n. Do it in-place and in one-pass. For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4, return 1->4->3->2->5->NULL. Note:Given m, n satisfy the following condition:1 ≤ m ≤ n ≤ lengt…
Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 click to show spoilers. Have you thought about this? Here are some good questions to ask before coding. Bonus points for you if you have already thought throu…
原题链接在这里:https://leetcode.com/problems/reverse-vowels-of-a-string/ 题目: Write a function that takes a string as input and reverse only the vowels of a string. Example 1:Given s = "hello", return "holle". Example 2:Given s = "leetcod…
原题链接在这里:https://leetcode.com/problems/reverse-string/ 题目: Write a function that takes a string as input and returns the string reversed. Example:Given s = "hello", return "olleh". 题解: Reverse string是常见题, string在Java中是primitive类型, 一旦生成不…
原题链接在这里:https://leetcode.com/problems/reverse-words-in-a-string-ii/ 题目: Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters. The input string does not contain leading or trailing spaces and…
Title: Given an input string, reverse the string word by word. For example,Given s = "the sky is blue",return "blue is sky the". https://leetcode.com/problems/reverse-words-in-a-string/ 思路:先将字符串全部逆转,在将每个单词逆转.具体实现,要注意空格,所以对字符串倒过来处理. cla…
Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Example 1: Input: "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc"…
Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. If there are less than 2k but greater than or eq…