Check for Contradictions in Equations - Solution & Explanation

You are given a 2D array of strings equations and an array of real numbers values, where equations[i] = [Ai, Bi] and values[i] means that Ai / Bi = values[i].

Determine if there exists a contradiction in the equations. Return true if there is a contradiction, or false otherwise.

Note:

• When checking if two numbers are equal, check that their absolute difference is less than 10-5.
• The testcases are generated such that there are no cases targeting precision, i.e. using double is enough to solve the problem.

 

Example 1:

Input: equations = [["a","b"],["b","c"],["a","c"]], values = [3,0.5,1.5]
Output: false
Explanation:
The given equations are: a / b = 3, b / c = 0.5, a / c = 1.5
There are no contradictions in the equations. One possible assignment to satisfy all equations is:
a = 3, b = 1 and c = 2.

Example 2:

Input: equations = [["le","et"],["le","code"],["code","et"]], values = [2,5,0.5]
Output: true
Explanation:
The given equations are: le / et = 2, le / code = 5, code / et = 0.5
Based on the first two equations, we get code / et = 0.4.
Since the third equation is code / et = 0.5, we get a contradiction.

 

Constraints:

• 1 <= equations.length <= 100
• equations[i].length == 2
• 1 <= Ai.length, Bi.length <= 5
• Ai, Bi consist of lowercase English letters.
• equations.length == values.length
• 0.0 < values[i] <= 10.0
• values[i] has a maximum of 2 decimal places.