public class Solution
extends Object
990 - Satisfiability of Equality Equations\.
Medium
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.
**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.