1312. Minimum Insertion Steps to Make a String Palindrome - LeetCode Solution

class Solution:
    def minInsertions(self, s: str) -> int:
        a = s
        b = s[::-1]
        
        t = []
        
        for i in range(len(a) + 1):
            l = []
            for j in range(len(b) + 1):
                l.append(0)
            t.append(l)
        
        for i in range(1, len(a) +1, 1):
            for j in range(1, len(b) + 1, 1):
                if a[i-1] == b[j-1]:
                    t[i][j] = 1 + t[i-1][j-1]
                else:
                    t[i][j] = max(t[i-1][j], t[i][j-1])
        
        return len(a) - t[len(a)][len(b)]