Given an array equations of strings that represent
relationships between variables, each string equations[i] has length
4 and takes one of two different forms: "a==b" or "a!=b".
Here, a and b are lowercase letters (not necessarily different)
that represent one-letter variable names.
Return true if and only if it is possible to assign integers to variable
names so as to satisfy all the given equations.
Example 1:
Input: ["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: ["b==a","a==b"] Output: true Explanation: We could assign a = 1 and b = 1 to satisfy both equations.
Example 3:
Input: ["a==b","b==c","a==c"] Output: true
Example 4:
Input: ["a==b","b!=c","c==a"] Output: false
Example 5:
Input: ["c==c","b==d","x!=z"] Output: true
Note:
1 <= equations.length <= 500equations[i].length == 4equations[i][0] and equations[i][3] are
lowercase letters
equations[i][1] is either '=' or
'!'equations[i][2] is '='