leetcode1143

经典的动态规划题目：最长公共子序列(Longest Common Subsequence)，使用二维数组记录，双层循环。

 1 class Solution:
 2     def longestCommonSubsequence(self, text1: str, text2: str) -> int:
 3         n1,n2 = len(text1),len(text2)
 4         if n1 == 0 or n2 == 0:
 5             return 0
 6         dp = [[0 for _ in range(n2+1)]for _ in range(n1+1)]
 7         for i in range(1,n1+1):
 8             for j in range(1,n2+1):
 9                 if text1[i-1] == text2[j-1]:
10                     dp[i][j] = dp[i-1][j-1] + 1
11                 else:
12                     dp[i][j] = max(dp[i][j-1],dp[i-1][j])
13         return dp[n1][n2]