mirror of
https://github.com/golang/go
synced 2024-11-25 06:27:57 -07:00
0dbd8971a2
- runs approx. 30% faster R=r DELTA=24 (10 added, 2 deleted, 12 changed) OCL=32984 CL=33005
130 lines
3.2 KiB
Go
130 lines
3.2 KiB
Go
/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of "The Computer Language Benchmarks Game" nor the
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name of "The Computer Language Shootout Benchmarks" nor the names of
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its contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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/* The Computer Language Benchmarks Game
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* http://shootout.alioth.debian.org/
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*
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* contributed by The Go Authors.
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* based on pidigits.c (by Paolo Bonzini & Sean Bartlett,
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* modified by Michael Mellor)
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*/
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package main
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import (
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"bignum";
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"flag";
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"fmt";
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)
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var n = flag.Int("n", 27, "number of digits");
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var silent = flag.Bool("s", false, "don't print result");
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var (
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tmp1 *bignum.Integer;
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tmp2 *bignum.Integer;
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numer = bignum.Int(1);
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accum = bignum.Int(0);
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denom = bignum.Int(1);
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)
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func extract_digit() int64 {
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if numer.Cmp(accum) > 0 {
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return -1;
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}
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// Compute (numer * 3 + accum) / denom
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tmp1 = numer.Shl(1);
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bignum.Iadd(tmp1, tmp1, numer);
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bignum.Iadd(tmp1, tmp1, accum);
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tmp1, tmp2 := tmp1.QuoRem(denom);
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// Now, if (numer * 4 + accum) % denom...
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bignum.Iadd(tmp2, tmp2, numer);
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// ... is normalized, then the two divisions have the same result.
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if tmp2.Cmp(denom) >= 0 {
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return -1;
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}
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return tmp1.Value();
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}
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func next_term(k int64) {
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y2 := k*2 + 1;
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tmp1 = numer.Shl(1);
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bignum.Iadd(accum, accum, tmp1);
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bignum.Iscale(accum, y2);
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bignum.Iscale(numer, k);
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bignum.Iscale(denom, y2);
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}
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func eliminate_digit(d int64) {
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bignum.Isub(accum, accum, denom.Mul1(d));
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bignum.Iscale(accum, 10);
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bignum.Iscale(numer, 10);
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}
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func printf(s string, arg ...) {
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if !*silent {
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fmt.Printf(s, arg);
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}
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}
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func main() {
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flag.Parse();
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var m int; // 0 <= m < 10
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for i, k := 0, int64(0); ; {
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d := int64(-1);
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for d < 0 {
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k++;
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next_term(k);
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d = extract_digit();
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}
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printf("%c", d + '0');
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i++;
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m = i%10;
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if m == 0 {
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printf("\t:%d\n", i);
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}
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if i >= *n {
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break;
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}
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eliminate_digit(d);
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}
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if m > 0 {
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printf("%s\t:%d\n", " "[m : 10], *n);
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}
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}
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