Goal
The Problem:
Write a program to input the condensed formula of an alicylic hydrocarbon, and decide whether it is valid or not.
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Condensed Formula:
The condensed formula includes units of carbon linked to one another by one or more bonds.
1 unit of carbon is represented as CHn.
The bonds are adjacent to the carbon units, either horizontally or vertically. Bonds are represented as (m).
The inputs given will have a valid representation, but the bonds might not be matching. For example, a carbon unit with n=1 should have 3 adjacent bonds, one with n=2 should have 2 adjacent bonds, etc.
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Note:
To get a better understanding of organic compounds and condensed formulae, look it up on the web
Input
Line 1: An integer N, denoting the number of lines
Next N Lines: String COMPOUND representing the hydrocarbon
Output
If the hydrocarbon is valid, a single line VALID.
If it is not valid, a single line INVALID.
Constraints
1≤N≤20
In carbon units, 0≤n≤4
In bonds, 0<m≤4
