problem: https://oj.leetcode.com/problems/word-ladder-ii/
代码:https://play.golang.org/p/qdmadQUcEC
package main
import (
"fmt"
)
func main() {
start := "hit"
end := "cog"
dict := []string{"hot", "dot", "dog", "lot", "log"}
dict = append(dict, start, end)
mapAdjacency := createAdjacencyGraph(dict, start, end)
findLadders(mapAdjacency, start, end)
}
func findLadders(mapAdjacency map[string][]string, start, end string) {
visited := make(map[string]int, len(mapAdjacency))
visited[start] = 1
queue := make([]string, len(mapAdjacency))
queue = append(queue, start)
mapParent := make(map[string][]string, len(mapAdjacency))
bfs(mapAdjacency, visited, queue, mapParent, start, end)
stack := []string{}
stack = append(stack, end)
printShortestPath(mapParent, stack, start, end)
}
func printShortestPath(mapParent map[string][]string, stack []string, start, end string) {
if end == start {
printStack(stack)
return
}
for _, v := range mapParent[end] {
stack = append(stack, v)
printShortestPath(mapParent, stack, start, v)
stack = stack[:len(stack)-1]
}
}
func printStack(stack []string) {
lenStack := len(stack)
for i := lenStack - 1; i >= 0; i-- {
fmt.Printf("%s ", stack[i])
}
fmt.Println()
}
func bfs(mapAdjacency map[string][]string, visited map[string]int, queue []string,
mapParent map[string][]string, start string, end string) {
var cur string
for len(queue) > 0 {
//出队列
cur, queue = queue[0], queue[1:]
for _, value := range mapAdjacency[cur] {
if visited[value] == 0 {
//入队列
queue = append(queue, value)
visited[value] = visited[cur] + 1
mapParent[value] = append(mapParent[value], cur)
} else if visited[value] > visited[cur] {
mapParent[value] = append(mapParent[value], cur)
}
}
}
}
func createAdjacencyGraph(dict []string, start, end string) (mapAdjacency map[string][]string) {
mapAdjacency = make(map[string][]string)
lenWord := len(start)
for _, vi := range dict {
for _, vj := range dict {
count := 0
if vi != vj {
for k := 0; k < lenWord; k++ {
if vi[k] == vj[k] {
count++
}
}
if count == lenWord-1 { //find adjacency
mapAdjacency[vi] = append(mapAdjacency[vi], vj)
}
}
}
}
return
}
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