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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /gcc/testsuite/go.test/test/bench/fannkuch.go
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Diffstat (limited to 'gcc/testsuite/go.test/test/bench/fannkuch.go')
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diff --git a/gcc/testsuite/go.test/test/bench/fannkuch.go b/gcc/testsuite/go.test/test/bench/fannkuch.go
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@@ -0,0 +1,122 @@
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ * Neither the name of "The Computer Language Benchmarks Game" nor the
+ name of "The Computer Language Shootout Benchmarks" nor the names of
+ its contributors may be used to endorse or promote products derived
+ from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*
+ * The Computer Language Benchmarks Game
+ * http://shootout.alioth.debian.org/
+ *
+ * contributed by The Go Authors.
+ * Based on fannkuch.c by Heiner Marxen
+ */
+
+package main
+
+import (
+ "flag"
+ "fmt"
+)
+
+var n = flag.Int("n", 7, "count")
+
+func fannkuch(n int) int {
+ if n < 1 {
+ return 0
+ }
+
+ n1 := n - 1
+ perm := make([]int, n)
+ perm1 := make([]int, n)
+ count := make([]int, n)
+
+ for i := 0; i < n; i++ {
+ perm1[i] = i // initial (trivial) permutation
+ }
+
+ r := n
+ didpr := 0
+ flipsMax := 0
+ for {
+ if didpr < 30 {
+ for i := 0; i < n; i++ {
+ fmt.Printf("%d", 1+perm1[i])
+ }
+ fmt.Printf("\n")
+ didpr++
+ }
+ for ; r != 1; r-- {
+ count[r-1] = r
+ }
+
+ if perm1[0] != 0 && perm1[n1] != n1 {
+ flips := 0
+ for i := 1; i < n; i++ { // perm = perm1
+ perm[i] = perm1[i]
+ }
+ k := perm1[0] // cache perm[0] in k
+ for { // k!=0 ==> k>0
+ for i, j := 1, k-1; i < j; i, j = i+1, j-1 {
+ perm[i], perm[j] = perm[j], perm[i]
+ }
+ flips++
+ // Now exchange k (caching perm[0]) and perm[k]... with care!
+ j := perm[k]
+ perm[k] = k
+ k = j
+ if k == 0 {
+ break
+ }
+ }
+ if flipsMax < flips {
+ flipsMax = flips
+ }
+ }
+
+ for ; r < n; r++ {
+ // rotate down perm[0..r] by one
+ perm0 := perm1[0]
+ for i := 0; i < r; i++ {
+ perm1[i] = perm1[i+1]
+ }
+ perm1[r] = perm0
+ count[r]--
+ if count[r] > 0 {
+ break
+ }
+ }
+ if r == n {
+ return flipsMax
+ }
+ }
+ return 0
+}
+
+func main() {
+ flag.Parse()
+ fmt.Printf("Pfannkuchen(%d) = %d\n", *n, fannkuch(*n))
+}