0990. Satisfiability of Equality Equations

https://leetcode.com/problems/satisfiability-of-equality-equations

Description

You are given an array of strings equations that represent relationships between variables where each string equations[i] is of length 4 and takes one of two different forms: "xi==yi" or "xi!=yi".Here, xi and yi are lowercase letters (not necessarily different) that represent one-letter variable names.

Return true if it is possible to assign integers to variable names so as to satisfy all the given equations, or false otherwise.

Example 1:

**Input:** equations = ["a==b","b!=a"]
**Output:** false
**Explanation:** If we assign say, a = 1 and b = 1, then the first equation is satisfied, but not the second.
There is no way to assign the variables to satisfy both equations.

Example 2:

**Input:** equations = ["b==a","a==b"]
**Output:** true
**Explanation:** We could assign a = 1 and b = 1 to satisfy both equations.

Example 3:

**Input:** equations = ["a==b","b==c","a==c"]
**Output:** true

Example 4:

**Input:** equations = ["a==b","b!=c","c==a"]
**Output:** false

Example 5:

**Input:** equations = ["c==c","b==d","x!=z"]
**Output:** true

Constraints:

• 1 <= equations.length <= 500

• equations[i].length == 4

• equations[i][0] is a lowercase letter.

• equations[i][1] is either '=' or '!'.

• equations[i][2] is '='.

• equations[i][3] is a lowercase letter.

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