36 lines
611 B
C
36 lines
611 B
C
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#include <stdio.h>
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#include <stdlib.h>
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unsigned long long fib_iter(unsigned long long a)
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{
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unsigned long long r = 0;
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unsigned long long minus_one = 1;
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unsigned long long minus_two = 0;
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unsigned long long i;
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if (a == 0) {
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r = 0;
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} else if (a == 1) {
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r = 1;
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} else {
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for (i = 2; i <= a; i++) {
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r = minus_one + minus_two;
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minus_two = minus_one;
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minus_one = r;
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}
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}
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return r;
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}
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int main(int argc, char *argv[])
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{
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unsigned long long a = 0;
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unsigned long long r = 0;
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a = atol(argv[1]);
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r = fib_iter(a);
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printf("fib(%llu) = %llu\n",a,r);
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return 0;
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}
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