What is difference between the two codes mentioned below? Its a simple LCS problem of DSA

Question

class Solution:
    def longestCommonSubsequ

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ence(self, text1: str, text2: str) -> int: dp = [[-1 for i in range(len(text2))]for i in range(len(text1))] def helper(i, j): if i < 0 or j < 0: return 0 if dp[i][j] != -1: return dp[i][j] if text1[i] == text2[j]: dp[i][j] = helper(i-1, j-1)+1 else: dp[i][j] = max(helper(i-1, j), helper(i, j-1)) return dp[i][j] return helper(len(text1)-1, len(text2)-1)

Problem link can be found here: https://leetcode.com/problems/longest-common-subsequence/

The code mentioned first does not work, but if I shift the first two statements below then it works. What is the explanations?

class Solution: def longestCommonSubsequence(self, text1: str, text2: str) -> int: dp = [[-1 for i in range(len(text2))]for i in range(len(text1))] def helper(i, j): if dp[i][j] != -1: return dp[i][j] if i < 0 or j < 0: return 0 if text1[i] == text2[j]: dp[i][j] = helper(i-1, j-1)+1 else: dp[i][j] = max(helper(i-1, j), helper(i, j-1)) return dp[i][j] return helper(len(text1)-1, len(text2)-1)

class Solution: def longestCommonSubsequence(self, text1: str, text2: str) -> int: dp = [[-1 for i in range(len(text2))]for i in range(len(text1))] def helper(i, j): if i < 0 or j < 0: return 0 if dp[i][j] != -1: return dp[i][j] if text1[i] == text2[j]: dp[i][j] = helper(i-1, j-1)+1 else: dp[i][j] = max(helper(i-1, j), helper(i, j-1)) return dp[i][j] return helper(len(text1)-1, len(text2)-1)