[LeetCode OJ] Decode Ways

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[LeetCode OJ] Decode Ways

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given encoded…

leetcode@ [91] Decode Ways (Dynamic Programming)

https://leetcode.com/problems/decode-ways/ A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of wa…

leetcode 91 Decode Ways I

令dp[i]为从0到i的总方法数,那么很容易得出dp[i]=dp[i-1]+dp[i-2], 即当我们以i为结尾的时候,可以将i单独作为一个字母decode (dp[i-1]),同时也可以将i和i-1作为两个字母组合进行decode. 关键在于出现0的情况,当i-1为0的时候,我们不能将i和i-1进行组合,因为0不能作为前缀进行decode,此时dp[i]=dp[i-1],当i为0的时候,我们不能不能单独decode i,此时dp[i]=dp[i-2] 另外由于我们只需要保存前两步的状态,因此可…

Leetcode 91. Decode Ways 解码方法(动态规划，字符串处理)

Leetcode 91. Decode Ways 解码方法(动态规划,字符串处理) 题目描述一条报文包含字母A-Z,使用下面的字母-数字映射进行解码 'A' -> 1 'B' -> 2 ... 'Z' -> 26 给一串包含数字的加密报文,求有多少种解码方式举个例子,已知报文"12",它可以解码为AB(1 2),也可以是L (12) 所以解码方式有2种. 测试样例 Input: "0" "121212" "1010…

[LeetCode] 639. Decode Ways II 解码方法 II

A message containing letters from A-Z is being encoded to numbers using the following mapping way: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Beyond that, now the encoded string can also contain the character '*', which can be treated as one of the numbers…

[LeetCode] 91. Decode Ways 解码方法

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given a non-empty string containing only digits, determine the total number of ways to decode it. Example 1: Input: &qu…

leetcode 639 Decode Ways II

首先回顾一下decode ways I 的做法:链接分情况讨论 if s[i]=='*' 考虑s[i]单独decode,由于s[i]肯定不会为0,因此我们可以放心的dp+=dp1 再考虑s[i-1]和s[i]decode,如果s[i-1]为*,那么**的组合共有15种(11,12,13.....,21,22..26),注意不是9*9=81种,因为我们是s[i-1]和s[i]一起decode,如果是38这样是大于26的如果s[i-1]不为*,枚举s[i],组合起来小于26即可 if s[i]!…

【leetcode】Decode Ways(medium)

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given encoded…

leetcode 91 Decode Ways ----- java

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given encoded…

[leetcode]91. Decode Ways解码方法

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given a non-empty string containing only digits, determine the total number of ways to decode it. Example 1: Input: &qu…

LeetCode之Decode Ways

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example, Given encoded…

Java for LeetCode 091 Decode Ways

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example, Given encoded…

Leetcode#91 Decode Ways

原题地址动态规划题,注意0导致的小陷阱. 代码: int numDecodings(string s) { ] < ] > ; ] >= ] <= : ; ; int next = sum; ; i >= ; i--) { ') { ] >= ] <= ')) sum = next + nextnext; ') sum = ; else sum = next; nextnext = next; next = sum; } else ; } return sum;…

leetcode[90] Decode Ways

题目:如下对应关系 'A' -> 1 'B' -> 2 ... ‘Z’ -> 26 现在给定一个字符串,返回有多少种解码可能.例如:Given encoded message "12", it could be decoded as "AB" (1 2) or "L" (12). 思路:动态规划. dp[i]表示s[0,...,i-1]的种数. 那么dp[i]和dp[i-1]存在什么关系呢. 我们设singleVal为dp[i-…

【leetcode】Decode Ways

题目如下: 解题思路:这个题目的本质是一个爬楼梯问题,在爬楼梯问题中,每次可以选择走一步或者两步.而本题也是一样的,解码的时候选择解码一个字符或者两个字符,但是加大了一点点难度,要考虑这些情况.1,Z对应的编码是26,所以超过26的连续两个字符不能合并解码,27只能解析成2和7:2,0字符只能和前面的字符合并解码,不能单独作为一个字符解码. 代码如下: /** * @param {string} s * @return {number} */ var numDecodings = functio…

[LeetCode] Decode Ways 解码方法

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given encoded…

leetcode面试准备:Decode Ways

1 题目 A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example, Given en…

[LeetCode] Decode Ways II 解码方法之二

A message containing letters from A-Z is being encoded to numbers using the following mapping way: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Beyond that, now the encoded string can also contain the character '*', which can be treated as one of the numbers…

动态规划小结 - 一维动态规划 - 时间复杂度 O(n)，题 [LeetCode] Jump Game，Decode Ways

引言一维动态规划根据转移方程,复杂度一般有两种情况. func(i) 只和 func(i-1)有关,时间复杂度是O(n),这种情况下空间复杂度往往可以优化为O(1) func(i) 和 func(1~i-1)有关,时间复杂度是O(n*n),这种情况下空间复杂度一般无法优化,依然为O(n) 本篇讨论第一种情况例题 1 Jump Game Given an array of non-negative integers, you are initially positioned at the fi…

LeetCode解题报告—— Word Search & Subsets II & Decode Ways

1. Word Search Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cel…

【LeetCode】91. Decode Ways 解题报告（Python）

[LeetCode]91. Decode Ways 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/decode-ways/description/ 题目描述: A message containing letters from A-Z is being encoded to numbers usin…

Decode Ways leetcode java

题目: A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example, Given enc…

LeetCode:Decode Ways 解题报告

Decode WaysA message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1'B' -> 2...'Z' -> 26Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given e…

【LeetCode】091. Decode Ways

题目: A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine the total number of ways to decode it. For example,Given enco…

LeetCode OJ 题解

博客搬至blog.csgrandeur.com,cnblogs不再更新. 新的题解会更新在新博客:http://blog.csgrandeur.com/2014/01/15/LeetCode-OJ-Solution/ ———————————————————————————————————————— ———————————————————————————————————————— LeetCode OJ 题解 LeetCode OJ is a platform for preparing tech…