Python Counter and Dictionary Intersection Example (Make a string using deletion and rearrangement) (original) (raw)

Last Updated : 31 Oct, 2025

Given two strings, check if it is possible to make the first string from the second by deleting some characters from the second string and rearranging the remaining characters.

**Examples:

Input : s1 = BOBthebuilder
: s2 = fBoOkBIHnfndBthesibuishlider
Output : Possible

Input : s1 = Hello
: s2 = dnaKfhelddf
Output : Not Possible

**Approach:

**1. Count each character in both strings

• We use Python’s Counter from the collections module.
• Counter(str1) gives a dictionary-like object showing how many times each character appears in str1.
• Similarly, Counter(str2) counts characters in str2.

**2. Compare character counts

• For each character in str1, we check if str2 has that character in equal or greater quantity.
• Example:
  • If str1 needs 2 'A's, then str2 must have at least 2 'A's.
  • If even one character from str1 is missing or appears fewer times in str2, then the answer is “Not Possible.”

**3. Decide the result

• If all characters in str1 are found in sufficient quantity in str2, print “Possible.”
• Otherwise, print “Not Possible.”

**Implementation:

Python `

from collections import Counter

s1 = 'BOBthebuilder' s2 = 'fBoOkBIHnfndBthesibuishlider'

Count characters in both strings

count1 = Counter(s1) count2 = Counter(s2)

Check if all characters of str1 are present in str2

possible = True for ch in count1: if count1[ch] > count2[ch]: possible = False break

if possible: print("Possible") else: print("Not Possible")

`

**Explanation:

• We use Counter to count how many times each character appears.
• Then we check, one by one, if str2 has enough of each character.
• If any character is missing or fewer, it prints “Not Possible”.
• Otherwise, it prints “Possible”.

Related Articles:

• Operations on Python Counter
• Python Collections Counter