53 lines
807 B
Matlab
53 lines
807 B
Matlab
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//
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// Shuffle.m
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// Cog
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//
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// Created by Zaphod Beeblebrox on 1/14/06.
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// Copyright 2006 __MyCompanyName__. All rights reserved.
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//
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#import "Shuffle.h"
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@implementation Shuffle
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int sum(int n)
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{
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return (n*n+n)/2;
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}
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int reverse_sum(int n)
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{
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return (int)(ceil((-1.0 + sqrt(1.0 + 8.0*n))/2.0));
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}
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int randint(int low, int high)
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{
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return (random()%high)+low;
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}
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+ (NSMutableArray *)shuffleList:(NSArray *)l
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{
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NSMutableArray *a = [l mutableCopy];
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NSMutableArray *b = [[NSMutableArray alloc] init];
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while([a count] > 0)
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{
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int t, r, p;
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t = sum([a count]);
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r = randint(1, t);
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p = reverse_sum(r) - 1;
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printf("%i, %i, %i, %i\n", [a count], t, r, p);
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[b insertObject:[a objectAtIndex:p] atIndex:0];
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[a removeObjectAtIndex:p];
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}
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[a release];
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return [b autorelease];
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}
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@end
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