From 9efd29eaca734da227eb470cf5fcc95d296acc6a Mon Sep 17 00:00:00 2001
From: Pedram_Mohajer <48964282+pedram-mohajer@users.noreply.github.com>
Date: Mon, 20 Nov 2023 22:36:58 -0500
Subject: [PATCH 1/2] Update edit_distance.py

---
 strings/edit_distance.py | 51 ++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/strings/edit_distance.py b/strings/edit_distance.py
index e842c8555c8e..ff56e7cb0d4a 100644
--- a/strings/edit_distance.py
+++ b/strings/edit_distance.py
@@ -1,32 +1,43 @@
 def edit_distance(source: str, target: str) -> int:
     """
-    Edit distance algorithm is a string metric, i.e., it is a way of quantifying how
-    dissimilar two strings are to one another. It is measured by counting the minimum
-    number of operations required to transform one string into another.
-
-    This implementation assumes that the cost of operations (insertion, deletion and
-    substitution) is always 1
+    Calculate the edit distance between two strings using dynamic programming.
+    Edit distance is the minimum number of operations (insertions, deletions, or
+    substitutions) required to transform one string into another.
 
     Args:
-    source: the initial string with respect to which we are calculating the edit
-        distance for the target
-    target: the target string, formed after performing n operations on the source string
+    source (str): The original string.
+    target (str): The string to transform into.
+
+    Returns:
+    int: The minimum number of operations required.
 
+    Examples:
     >>> edit_distance("GATTIC", "GALTIC")
     1
+    >>> edit_distance("ATCGCTG", "TAGCTAA")
+    4
     """
-    if len(source) == 0:
-        return len(target)
-    elif len(target) == 0:
-        return len(source)
 
-    delta = int(source[-1] != target[-1])  # Substitution
-    return min(
-        edit_distance(source[:-1], target[:-1]) + delta,
-        edit_distance(source, target[:-1]) + 1,
-        edit_distance(source[:-1], target) + 1,
-    )
+    dp = [[0 for _ in range(len(target) + 1)] for _ in range(len(source) + 1)]
+
+    # Populate the matrix
+    for i in range(len(source) + 1):
+        for j in range(len(target) + 1):
+            if i == 0:
+                dp[i][j] = j
+            elif j == 0:
+                dp[i][j] = i
+            elif source[i - 1] == target[j - 1]:
+                dp[i][j] = dp[i - 1][j - 1]
+            else:
+                dp[i][j] = 1 + min(
+                    dp[i - 1][j], dp[i][j - 1], dp[i - 1][j - 1]  # Remove  # Insert
+                )  # Replace
+
+    return dp[len(source)][len(target)]
 
 
 if __name__ == "__main__":
-    print(edit_distance("ATCGCTG", "TAGCTAA"))  # Answer is 4
+    print(edit_distance("GATTIC", "GALTIC"))  # Output: 1
+    print(edit_distance("ATCGCTG", "TAGCTAA"))  # Output: 4
+

From eade82215b3252d0d226ec955983fc9afbdfbfcd Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 21 Nov 2023 03:44:10 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 strings/edit_distance.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/strings/edit_distance.py b/strings/edit_distance.py
index ff56e7cb0d4a..c7a924c64549 100644
--- a/strings/edit_distance.py
+++ b/strings/edit_distance.py
@@ -40,4 +40,3 @@ def edit_distance(source: str, target: str) -> int:
 if __name__ == "__main__":
     print(edit_distance("GATTIC", "GALTIC"))  # Output: 1
     print(edit_distance("ATCGCTG", "TAGCTAA"))  # Output: 4
-