最长公共子序列程序抛出字符串索引超出范围错误

Question

我有两个字符串

str1 = "bqdrcvefgh"

str2 = "abcvdefgh"

我想找到两者之间的 LCS strings.But 我遇到字符串索引超出范围 exception.This 是我的代码

str1 = "bqdrcvefgh"
str2 = "abcvdefgh"
#taking str1 as column and str2 as row
lis = [[0]*(len(str1)+1) for i in range(len(str2)+1)]

#The first row and first column has default value of 0
for i in range(1,len(str2)+1):
    for j in range(1,len(str1)+1):
        if str2[i]==str1[j]:
            lis[i][j] = lis[i-1][j-1]+1
        else:
            lis[i][j] = max(lis[i][j-1],lis[i-1][j])

#length of the longest LCS
print(lis[len(str2)][len(str1)])

我做错了什么？

PS-正确答案是7

Answer 1

索引从零到 len-1 是运行（从 1 到 len 是运行）。

固定代码如下：

def lcs(str1, str2):    
    #taking str1 as column and str2 as row
    lis = [[0]*(len(str1)) for i in range(len(str2))]
    for i in range(len(str2)):
        for j in range(len(str1)):
            if str2[i]==str1[j]:
                lis[i][j] = lis[i-1][j-1]+1
            else:
                lis[i][j] = max(lis[i][j-1],lis[i-1][j])

    #length of the longest LCS
    print(lis[len(str2)-1][len(str1)-1])

str1 = "bqdrcvefgh"
str2 = "abcvdefgh"    
lcs(str1, str2)  # prints 7

最长公共子序列程序抛出字符串索引超出范围错误

Longest Common Subsequence program throws a string index out of range error

dynamic-programming

python-3.x

longest-substring