最长公共子序列

if str1[i] == str2[j]:
   dp[i][j] = dp[i-1][j-1] + 1
else:
 dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])

class :
    def find_lcs(self, str1, str2):
        size1 = len(str1)
        size2 = len(str2)
        
        dp = [[0 for i in range(size2+1)] for j in range(size1+1)]
        # 动态规划过程
        for i in range(1,size1+1):
            for j in range(1,size2+1):
                if str1[i-1] == str2[j-1]:
                    dp[i][j] = dp[i - 1][j - 1] + 1
                else:
                    dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])
        return dp[-1][-1]
        
# 例子
str1 = "ABCDEF"
str2 = "AEBDEDF"
print(Solution().find_lcs(str1, str2))