INT102-Longes-Common-Subsequences Dynamic Programming

 

 

import numpy as np


def LCS(X: str, Y: str) -> tuple:
    n, m = len(X), len(Y)
    dp = [[0 for col in range(m + 1)] for row in range(n + 1)]
    flag = [[" " for col in range(m + 1)] for row in range(n + 1)]
    for i in range(n):
        for j in range(m):
            if X[i] == Y[j]:
                dp[i + 1][j + 1] = dp[i][j] + 1
                flag[i + 1][j + 1] = '↖'
            elif dp[i + 1][j] > dp[i][j + 1]:
                dp[i + 1][j + 1] = dp[i + 1][j]
                flag[i + 1][j + 1] = '←'
            else:
                dp[i + 1][j + 1] = dp[i][j + 1]
                flag[i + 1][j + 1] = '↑'
    return dp, flag


if __name__ == '__main__':
    X = "GAGT"
    Y = "AGCCCT"
    dp, flag = LCS(X, Y)
    print(np.array(dp))
    print(np.array(flag))