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authorRob Pike <r@golang.org>2009-08-04 19:38:08 -0700
committerRob Pike <r@golang.org>2009-08-04 19:38:08 -0700
commit2f275dfe88e9b6dea79e2e269faf98370f513dd1 (patch)
tree1b7781ae8925b1d7b8b4e609311fe84967fff674 /test/bench/binary-tree.go
parent1b34f64196e8248d8538f066934621d0bcaefb90 (diff)
downloadgolang-2f275dfe88e9b6dea79e2e269faf98370f513dd1.tar.gz
binary tree
R=rsc DELTA=324 (323 added, 0 deleted, 1 changed) OCL=32759 CL=32768
Diffstat (limited to 'test/bench/binary-tree.go')
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diff --git a/test/bench/binary-tree.go b/test/bench/binary-tree.go
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+++ b/test/bench/binary-tree.go
@@ -0,0 +1,93 @@
+/*
+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 C program by Kevin Carson
+ */
+
+package main
+
+import (
+ "flag";
+ "fmt";
+ "os";
+)
+
+var n = flag.Int("n", 20, "depth")
+
+type Node struct {
+ item int;
+ left, right *Node;
+}
+
+func bottomUpTree(item, depth int) *Node {
+ if depth <= 0 {
+ return &Node{item: item}
+ }
+ return &Node{ item, bottomUpTree(2*item-1, depth-1), bottomUpTree(2*item, depth-1) }
+}
+
+func (n *Node) itemCheck() int {
+ if n.left == nil {
+ return n.item
+ }
+ return n.item + n.left.itemCheck() - n.right.itemCheck();
+}
+
+const minDepth = 4;
+
+func main() {
+ flag.Parse();
+
+ maxDepth := *n;
+ if minDepth + 2 > *n {
+ maxDepth = minDepth + 2
+ }
+ stretchDepth := maxDepth + 1;
+
+ check := bottomUpTree(0, stretchDepth).itemCheck();
+ fmt.Println("stretch tree of depth ", stretchDepth, "\t check:", check);
+
+ longLivedTree := bottomUpTree(0, maxDepth);
+
+ for depth := minDepth; depth <= maxDepth; depth+=2 {
+ iterations := 1 << uint(maxDepth - depth + minDepth);
+ check = 0;
+
+ for i := 1; i <= iterations; i++ {
+ check += bottomUpTree(i,depth).itemCheck();
+ check += bottomUpTree(-i,depth).itemCheck();
+ }
+ fmt.Println(iterations*2, "\t trees of depth ", depth, "\t check: ", check);
+ }
+ fmt.Println("long lived tree of depth", maxDepth, "\t check:", longLivedTree.itemCheck());
+}