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ws.go
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ws.go
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package ws
import (
"fmt"
"github.com/catorpilor/leetcode/utils"
)
func findWords(board [][]byte, words []string) []string {
return backTrack(board, words)
}
func backTrack(board [][]byte, words []string) []string {
var res []string
n := len(board)
if n < 1 {
return res
}
m := len(board[0])
if m < 1 {
return res
}
for _, word := range words {
for i := 0; i < n; i++ {
for j := 0; j < m; j++ {
if helper(&res, word, board, i, j, n, m, 0) {
goto PP
}
}
}
PP:
}
return res
}
func helper(res *[]string, s string, board [][]byte, x, y, n, m, idx int) bool {
fmt.Printf("helper s:%s, x:%d, y:%d, idx:%d\n", s, x, y, idx)
if idx == len(s) {
*res = append(*res, s)
fmt.Printf("append to res:%v, s:%s\n", *res, s)
return true
}
if x < 0 || x >= n || y < 0 || y >= m {
return false
}
if board[x][y] != s[idx] {
return false
}
board[x][y] ^= 128
ret := helper(res, s, board, x, y+1, n, m, idx+1) || helper(res, s, board, x, y-1, n, m, idx+1) ||
helper(res, s, board, x-1, y, n, m, idx+1) || helper(res, s, board, x+1, y, n, m, idx+1)
board[x][y] ^= 128
return ret
}
func withTSTTrie(board [][]byte, words []string) []string {
var res []string
n := len(board)
if n < 1 {
return res
}
m := len(board[0])
if m < 1 {
return res
}
tst := utils.NewTST()
for _, w := range words {
tst.Put(w, w)
}
for i := 0; i < n; i++ {
for j := 0; j < m; j++ {
permute(&res, board, tst.Root, i, j, n, m)
// fmt.Println("loop here")
}
}
return res
}
func permute(res *[]string, board [][]byte, node *utils.TSTNode, i, j, n, m int) {
if i < 0 || i >= n || j < 0 || j >= m {
return
}
c := board[i][j]
// fmt.Printf("node:%v, i:%d,j%d,c:%c\n", node, i, j, c)
if c == '#' || node == nil {
return
}
if node.Value != nil && node.Cb == c {
if s, ok := node.Value.(string); ok {
*res = append(*res, s)
node.Value = nil // remove duplicates
}
}
if c > node.Cb {
// fmt.Println("go right")
node = node.Right
permute(res, board, node, i, j, n, m)
} else if c < node.Cb {
// fmt.Println("go left")
node = node.Left
permute(res, board, node, i, j, n, m)
} else {
// fmt.Println("go middle")
node = node.Middle
board[i][j] = '#'
permute(res, board, node, i-1, j, n, m)
permute(res, board, node, i, j-1, n, m)
permute(res, board, node, i+1, j, n, m)
permute(res, board, node, i, j+1, n, m)
board[i][j] = c
}
}
func withRWayTrie(board [][]byte, words []string) []string {
var res []string
n := len(board)
if n < 1 {
return res
}
m := len(board[0])
if m < 1 {
return res
}
if len(words) < 1 {
return res
}
rtrie := utils.NewRTrie(26)
for _, w := range words {
rtrie.Put(w, w)
}
for i := 0; i < n; i++ {
for j := 0; j < m; j++ {
dfs(&res, board, rtrie.Root, i, j, n, m)
}
}
return res
}
func dfs(res *[]string, board [][]byte, node *utils.TrieNode, i, j, n, m int) {
c := board[i][j]
if c == '#' || node == nil {
return
}
idx := c - 'a'
node = node.Children[idx]
if node != nil && node.Value != nil {
if v, ok := node.Value.(string); ok {
*res = append(*res, v)
node.Value = nil
}
}
board[i][j] = '#'
if i > 0 {
dfs(res, board, node, i-1, j, n, m)
}
if j > 0 {
dfs(res, board, node, i, j-1, n, m)
}
if i < n-1 {
dfs(res, board, node, i+1, j, n, m)
}
if j < m-1 {
dfs(res, board, node, i, j+1, n, m)
}
board[i][j] = c
}