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WHAT IS ALGORITHM?
Algorithm is collection of steps for solving a problem
For getting output desired about input.
Basic issues related to algorithm
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How to design algorithm
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How to express algorithm
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Proving Correctness
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Efficiency (time & space)
Too much time/ Too much source is bad algorithm
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Optimality
Even though no matter how good a program, if this needs a lot of resources, then choose another program.
How good is the algorithm?
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Correctness
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Time efficiency = running time
The shorter running time, the better algorithm
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Space efficiency = memory
The less memory, the better algorithm
Algorithm‘s Requirements
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Finiteness
algorithm must terminate after running all steps.
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Definiteness
Instruction of algorithm, showing the contents and order of operations to perform, needs to explicitly specify.
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Input
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Output
Outputs the result of the value corresponding to the input value.
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Effectiveness
All steps are simple and must be feasible.
Why study algorithms?
Theoretical importance
Algorithm is core of the computer
Practical importance
possible to design and analyze an algorithm for a new problem, by learning algorithm.
Express algorithms
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Natural languages
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Pseudo code
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Flowcharts
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Programming language
Pseudo code
Flow chart