# Evaluate Division

Category

Graphs - DFS

Checkbox

Checkbox

Difficulty

Medium

Index

46

Key Ideas

The key idea to solve this problem is to use a graph and perform a depth-first search (DFS) or breadth-first search (BFS) to evaluate division between variables.

Problem Number

399

Problem Summary

### Problem Summary:
The "Evaluate Division" problem is number 399 in the LeetCode-75 curated list. It is categorized as a medium-level problem in the Graphs - DFS category. This problem involves evaluating division equations given as pairs of strings and calculating the result of division queries.
### Key Pitfalls:
- One key pitfall is handling scenarios where there are missing or undefined variables in the division equations.
- Another pitfall is efficiently building and traversing the graph to perform the division calculations.
- Additionally, handling cyclic dependencies in the equations requires careful consideration to avoid infinite loops.

Solution Summary

To solve problem number 399, Evaluate Division, a common approach is to use a graph-based algorithm called Depth-First Search (DFS). First, we build a directed graph where the nodes represent variables and the edges represent the division between variables. Then, we perform DFS to calculate the division between variables. During the DFS, we keep track of the current division value and update it accordingly. If a variable is not present in the graph or there is no path between two variables, we return -1. By carefully implementing the DFS algorithm, we can efficiently solve the problem and handle various test cases.

Tags

Array

Depth-First Search

Breadth-First Search