Minimum Genetic Mutation

The key idea

Problem

A gene string can be represented by an 8-character long string, with choices from 'A', 'C', 'G', and 'T'.

Suppose we need to investigate a mutation from a gene string startGene to a gene string endGene where one mutation is defined as one single character changed in the gene string.

There is also a gene bank that records all the valid gene mutations. A gene must be in bank to make it a valid gene string.

Given the two gene strings startGene and endGene and the gene bank, return the minimum number of mutations needed to mutate from startGene to endGene. If there is no such a mutation, return -1.

Note that the starting point is assumed to be valid, so it might not be included in the bank.

Constraints

• startGene.length == 8
• endGene.length == 8
• 0 <= bank.length <= 10
• bank[i].length == 8
• startGene, endGene, and bank[i] consist of only the characters ['A', 'C', 'G', 'T'].

Examples

Complexity

Time: O(B * L * 4) Space: O(B)

More BFS / DFS problems

• 01 MatrixMEDIUM
• Average of Levels in Binary TreeEASY
• Binary Tree Level Order TraversalMEDIUM
• Binary Tree Level Order Traversal IIMEDIUM
• Binary Tree Right Side ViewMEDIUM
• Binary Tree Zigzag Level Order TraversalMEDIUM
• Find Bottom Left Tree ValueMEDIUM
• Find Largest Value in Each Tree RowMEDIUM
• Flood FillEASY
• Keys and RoomsMEDIUM
• Max Area of IslandMEDIUM
• Maximum Level Sum of a Binary TreeMEDIUM