How to Solve Minimum Cost to Convert String I Leetcode Problem - Interview Coder Guide
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How to Solve Minimum Cost to Convert String I Problem

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Medium#3235
LeetCode Problem

Minimum Cost to Convert String I

You are given two 0-indexed strings source and target, both of length n and consisting of lowercase English letters. You are also given two 0-indexed character arrays original and changed, and an inte...

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Problem Breakdown

Understanding the Minimum Cost to Convert String I Problem

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Problem Statement

You are given two 0-indexed strings source and target, both of length n and consisting of lowercase English letters. You are also given two 0-indexed character arrays original and changed, and an integer array cost, where cost[i] represents the cost of changing the character original[i] to the character changed[i]. You start with the string source. In one operation, you can pick a character x from the string and change it to the character y at a cost of z if there exists any index j such that cost[j] == z, original[j] == x, and changed[j] == y. Return the minimum cost to convert the string source to the string target using any number of operations. If it is impossible to convert source to target, return -1. Note that there may exist indices i, j such that original[j] == original[i] and changed[j] == changed[i].

MediumProblem #3235
LeetCode

Minimum Cost to Convert String I

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Examples

Example 1
INPUT
source = "abcd", target = "acbe", original = ["a","b","c","c","e","d"], changed = ["b","c","b","e","b","e"], cost = [2,5,5,1,2,20]
OUTPUT
28
EXPLANATION

To convert the string "abcd" to string "acbe": - Change value at index 1 from 'b' to 'c' at a cost of 5. - Change value at index 2 from 'c' to 'e' at a cost of 1. - Change value at index 2 from 'e' to 'b' at a cost of 2. - Change value at index 3 from 'd' to 'e' at a cost of 20. The total cost incurred is 5 + 1 + 2 + 20 = 28. It can be shown that this is the minimum possible cost.

Example 2
INPUT
source = "aaaa", target = "bbbb", original = ["a","c"], changed = ["c","b"], cost = [1,2]
OUTPUT
12
EXPLANATION

To change the character 'a' to 'b' change the character 'a' to 'c' at a cost of 1, followed by changing the character 'c' to 'b' at a cost of 2, for a total cost of 1 + 2 = 3. To change all occurrences of 'a' to 'b', a total cost of 3 * 4 = 12 is incurred.

Example 3
INPUT
source = "abcd", target = "abce", original = ["a"], changed = ["e"], cost = [10000]
OUTPUT
-1
EXPLANATION

It is impossible to convert source to target because the value at index 3 cannot be changed from 'd' to '

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