hamilton/hamilton.go

package main

import (
	"fmt"
	"os"
)

var g [][]int = [][]int{
	[]int{1},
	[]int{0, 2},
	[]int{1, 3},
	[]int{2, 4},
	[]int{3, 5},
	[]int{4, 6, 14},
	[]int{5, 7},
	[]int{6, 8, 14},
	[]int{7, 9, 13},
	[]int{8, 10, 12},
	[]int{9, 11},
	[]int{10, 12, 15},
	[]int{9, 11, 13, 16},
	[]int{8, 12, 14, 17},
	[]int{5, 7, 13},
	[]int{11, 16},
	[]int{12, 15, 17},
	[]int{13, 16},
}

var step int

func writeGraphfile(g [][]int, path []int) {
	filename := fmt.Sprintf("step%07d.dot", step)
	f, _ := os.Create(filename)
	defer f.Close()
	step++
	fmt.Fprintln(f, "digraph {")
	fmt.Fprintln(f, "dpi=200")
	fmt.Fprintln(f, "node [shape=circle, style=filled, label=\"\"]")
	for v1, adjlist := range g {
		for _, v2 := range adjlist {
			fmt.Fprintln(f, v1, " -> ", v2)
		}
	}
	for i, _ := range g {
		fmt.Fprintln(f, i, "[xlabel=x]")
	}
	for i, v := range path {
		fmt.Fprintln(f, v, "[xlabel=", i, "]")
		fillcolor := "red"
		if i == 0 {
			fillcolor = "blue"
		} else if i == len(path)-1 {
			fillcolor = "yellow"
		}
		fmt.Fprintln(f, v, "[fillcolor=", fillcolor, "]")
	}
	fmt.Fprintln(f, "}")
}

func contains(path []int, v int) bool {
	for _, w := range path {
		if w == v {
			return true
		}
	}
	return false
}

func DFS(g [][]int, path []int) {
	deadend := true
	for _, v2 := range g[path[len(path)-1]] {
		if contains(path, v2) {
			continue
		}
		deadend = false
		path2 := append(path, v2)
		DFS(g, path2)
	}
	if len(path) == len(g) {
		fmt.Println("Found path: ", path)
		writeGraphfile(g, path)
		os.Exit(0)
	} else if deadend {
		writeGraphfile(g, path)
	}
}

func main() {
	step = 0
	writeGraphfile(g, []int{})
	DFS(g, []int{0})
	os.Exit(-1)
}