推荐本书

推荐本书，Grokking.Algorithms.An.illustrated.guide.for.programmers.and.other.curious.people
这本书很不错，讲的通俗易懂。而且都是实际的利用数据结构和算法解决问题，而没有把重点放在数据结构本身的实现上。

下面是两段代码分别是计算longest_common_substring和longest_common_subsequence.

#
def longest_common_substring(s1,s2):
    m=[[0] *(1+len(s2)) for i in range(1+len(s1))]
    longest,x_longest=0,0
    for x in range(1,1+len(s1)):
        for y in range(1,1+len(s2)):
            if s1[x-1] == s2[y-1]:
                m[x][y]=m[x-1][y-1]+1
                if m[x][y] > longest:
                    longest=m[x][y]
                    x_longest=x
            else:
                m[x][y]=0
    return s1[x_longest-longest: x_longest]

print(longest_common_substring("blue","clues"))

def longest_common_subsequence(s1,s2):
    m=[[0] *(1+len(s2)) for i in range(1+len(s1))]
    longest=0
    for x in range(1,1+len(s1)):
        for y in range(1,1+len(s2)):
            if s1[x-1] == s2[y-1]:
                m[x][y]=m[x-1][y-1]+1
                if m[x][y] > longest:
                    longest=m[x][y]

            else:
                m[x][y]=max(m[x-1][y],m[x][y-1])
    return longest

print(longest_common_subsequence("blue","clues"))
print(longest_common_subsequence("fish","fosh"))
print(longest_common_subsequence("fort","fosh"))

另附一个算法：
计算两个词之间的相似程度。
Linux 文件系统规范，我记得有这么个东西的。