<p>下面是一个简单的、基于动态规划的问题实现:</p>
<pre class="lang-py prettyprint-override"><code>def lcs(X, Y):
m, n = len(X), len(Y)
L = [[0 for x in xrange(n+1)] for x in xrange(m+1)]
# using a 2D Matrix for dynamic programming
# L[i][j] stores length of longest common string for X[0:i] and Y[0:j]
for i in range(m+1):
for j in range(n+1):
if i == 0 or j == 0:
L[i][j] = 0
elif X[i-1] == Y[j-1]:
L[i][j] = L[i-1][j-1] + 1
else:
L[i][j] = max(L[i-1][j], L[i][j-1])
# Following code is used to find the common string
index = L[m][n]
# Create a character array to store the lcs string
lcs = [""] * (index+1)
lcs[index] = ""
# Start from the right-most-bottom-most corner and
# one by one store characters in lcs[]
i = m
j = n
while i > 0 and j > 0:
# If current character in X[] and Y are same, then
# current character is part of LCS
if X[i-1] == Y[j-1]:
lcs[index-1] = X[i-1]
i-=1
j-=1
index-=1
# If not same, then find the larger of two and
# go in the direction of larger value
elif L[i-1][j] > L[i][j-1]:
i-=1
else:
j-=1
print ("".join(lcs))
</code></pre>