SOLUTION 2: http://www.ninechapter.com/solutions/ GITHUB: https://github.com/yuzhangcmu/LeetCode_algorithm/blob/master/dp/NumDecodings.java
接下来怎么dp才是难点,对于message中的位置i, 如果这个位置上的数字是1到9的那么这个数字和dp[i-1]是一种组合,如果这个数字和前一个构成的数在10到26之间,那么这两个数字和dp[i-2]又能构成一种decode way。 importjava.util.*;publicclassLeetCode{publicstaticvoidmain(String[] args){ Scanner sc=newSca...
Given an encoded message containing digits, determine the total number of ways to decode it. For example, Given encoded message "12", it could be decoded as "AB" (1 2) or "L" (12). The number of ways decoding "12"...
Beyond that, now the encoded string can also contain the character ‘*’, which can be treated as one of the numbers from 1 to 9. Given the encoded message containing digits and the character ‘*’, return the total number of ways to decode it. Also, since the answer may be very lar...
639 Decode Ways II 解码方法 II Description: A message containing letters from A-Z can be encoded into numbers using the following mapping: 'A' -> "1" 'B' -> "2" ... 'Z' -> "26" To decode an encoded message, all the digits must be grouped then mapped back into letters using ...
引入一个数组dp[],用来记录以某个字符为开始的解码数。动态规划其实就是一个填表的过程。整个过程的目标就是要填好新增的dp[]数组。public int numDecodings(String s) { if (s == null || s.length() == 0) { return 0; } int len = s.length(); ...
综上,s[i−1]=="1"or(s[i−1]=="2"and"1"<=s[i]<="6") 。此时,dp[i+1]=dp[i]+dp[i−1],等于上一位和上上位的解码方法之和。 否则,dp[i+1]=dp[i] 返回dp[n]复杂度分析时间复杂度:O(n) 空间复杂度:O(n)Pythonclass Solution: ...
class Solution{public:intnumDecodings(string s){if(s.empty())return0;vector<int>dp(s.size()+1,0);dp[0]=1;for(inti=1;i<dp.size();++i){if(s[i-1]!='0')dp[i]+=dp[i-1];if(i>=2&&s.substr(i-2,2)<="26"&&s.substr(i-2,2)>="10"){dp[i]+=dp[i-2];}}returndp...
leetcode 639 Decode Ways II链接 classSolution{ public: intnumDecodings(strings){ intdp1=,dp2=,now; if(s.length()==)return; if(s[]!='')dp1=; for(inti=;i<s.length();i++){ now=s[i]!=''?dp1:; if((s[i-]!='')&&((s[i-]-'')*+s[i]-''<=))now+=i-<?:dp2;//要...
Leetcode 91. Decode Ways JAVA语言 2 3 4 5 6 7 8 9 10 11 12 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 ...