I have a file with 100000 line when am using System.in it takes more than 1 minute to get the input but when I use a file to read the input it doesn't take time. what is the solution to keep using System.in but with more speed?
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i am a new user i accept questions but u know sometimes you cant what can i do!!!? – Hussein Zawawi Nov 03 '11 at 12:19
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You can always accept an answer, just click the tick below the vote count on the left. – Polynomial Nov 03 '11 at 12:22
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even if does not answer the subject how it comes? – Hussein Zawawi Nov 03 '11 at 18:45
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System.in reads line by line not the file contents at a time.So it is slow.
Android Killer
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System.in is inherently slow because it's taking the data in line by line (checking for newlines), rather than doing a large block copy from a file mapped in virtual memory.
There's no real way to speed up System.in, and this sounds like a situation where reading a file would be much more ideal.
Update: You may want to look at this question: What's the fastest way to read from System.in in Java?
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Polynomial
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Could you not change it so the string that goes to `System.in` is a path to the file, then parse it out from there? – Polynomial Nov 03 '11 at 12:15
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i wish :S it doesnt make any sense http://livearchive.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=378&page=show_problem&problem=2968 – Hussein Zawawi Nov 03 '11 at 12:17
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You need to use StringTokenizer if you want to read file very fast. https://docs.oracle.com/javase/7/docs/api/java/util/StringTokenizer.html
Aleksandr Lovkov
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Try to change the stream of system.in
System.setIn(new FileInputStream(fileName));
shift66
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