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SPOJ Problem Set (classical)
4031. Mass of Molecule
Problem code: MMASS
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A molecule can be defined as a sequence of atoms and represented by
a chemical formula consisting of letters denoting these atoms. E.g.
letter H denotes atom of hydrogen, C denotes atom of carbon, O denotes
atom of oxygen, formula COOH represents molecule consisting of
one atom of carbon, two atoms of oxygen and one atom of hydrogen.
To write some formulas efficiently, we use the following rules.
Letters denoting some atoms can be grouped by enclosing in parentheses,
e.g. formula CH(OH) contains group OH. Groups can be nested – a
group can also contain other groups. To simplify a formula,
consecutive occurrences of the same letter can be replaced with
that letter followed by a number of these occurrences. E.g. formula
COOHHH can be written as CO2H3 and it represents a molecule consisting
of one atom of carbon, two atoms of oxygen and three atoms of hydrogen.
Furthermore, consecutive occurrences of the same group can be replaced
with that group followed by a number of these occurrences.
E.g. formula CH (CO2H) (CO2H) (CO2H) can be written as CH(CO2H)3 and
molecule represented by both those formulas consists of four atoms of
carbon, four atoms of hydrogen and six atoms of oxygen.
A number written
after a letter or a group is always greater than or equal to 2 and less
than or equal to 9.
A mass of a molecule is a sum of masses of all its atoms. One atom of
hydrogen has mass 1, one atom of carbon has mass 12 and one atom of oxygen
has mass 16.
Write a program that will calculate a mass of a molecule.
Input
The first and only line of input file contains a formula of a molecule whose
mass needs to be determined. A formula of a molecule will consist of
characters H, C, O, (, ) , 2, 3, ..., 9 only. Its length will be less
or equal to 100 characters.
Output
The first and only line of output file should contain a mass of a molecule
represented with a given formula. The result will always be less than or
equal to 10,000.
Sample
MASS.IN
COOH
MASS.OUT
45
MASS.IN
CH(CO2H)3
MASS.OUT
148
MASS.IN
((CH)2(OH2H)(C(H))O)3
MASS.OUT
222
| Added by: | ~!(*(@*!@^& |
| Date: | 2009-03-08 |
| Time limit: | 1s
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| Source limit: | 50000B |
| Languages: | All except: CLOJ ERL F# JS PERL 6 TECS |
| Resource: | COI 01 |
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