adds common child problem - Longest Common Subsequence (LCS)

InterviewPreparationKit/StringManipulation/common_child.py

@@ -0,0 +1,56 @@
+#!/bin/python3
+
+# A string is said to be a child of a another string if it can be formed by deleting 0 or more characters from the other string. Letters cannot be rearranged. Given two strings of equal length, what's the longest string that can be constructed such that it is a child of both?
+
+
+import math
+import os
+import random
+import re
+import sys
+
+#
+# Complete the 'commonChild' function below.
+#
+# The function is expected to return an INTEGER.
+# The function accepts following parameters:
+# 1. STRING s1
+# 2. STRING s2
+#
+
+def commonChild(s1, s2):
+ # check limits
+ ls1 = len(s1)
+ ls2 = len(s2)
+ if 1 > ls1 & ls2 > 5000:
+ return 'out of memory'
+
+ max_at = {}
+ for item1 in s1:
+ current_max = 0
+
+ for i, item2 in enumerate(s2):
+ potential_sum = current_max + 1
+ current_max = max(current_max, max_at.get(i, 0))
+ if item1 == item2:
+ max_at[i] = potential_sum
+ return max(max_at.values(), default=0)
+
+ """
+ .... OLD .... ---> wrong: matching shouldn't intersect --> sequence is important
+ res = []
+ for item in s2:
+ if item in s1 and item not in res:
+ res.append(item)
+ print(res)
+ return len(res)
+ """
+
+if __name__ == '__main__':
+ # fptr = open(os.environ['OUTPUT_PATH'], 'w')
+ s1 = 'SHINCHAN' # input() # SHINCHAN
+ s2 = 'NOHARAAA' # input() # NOHARAAA
+ result = commonChild(s1, s2)
+ print(result)
+ # fptr.write(str(result) + '\n')
+ # fptr.close()