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c.go
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c.go
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package main
func hasValidPath(grid [][]int) bool {
n, m := len(grid), len(grid[0])
// 右下左上
dir4 := [4][2]int{{0, 1}, {1, 0}, {0, -1}, {-1, 0}}
dir4ID := [6][2]int{{0, 2}, {1, 3}, {1, 2}, {0, 1}, {2, 3}, {0, 3}}
g := make([][]int, n*m)
for i, row := range grid {
for j, street := range row {
v := i*m + j
for _, id := range dir4ID[street-1] {
d := dir4[id]
if x, y := i+d[0], j+d[1]; x >= 0 && x < n && y >= 0 && y < m {
g[v] = append(g[v], x*m+y)
} else {
g[v] = append(g[v], -1)
}
}
}
}
vis := make([]bool, n*m)
var f func(v int) bool
f = func(v int) bool {
if v == n*m-1 {
return true
}
vis[v] = true
for _, w := range g[v] {
if w != -1 && !vis[w] && (g[w][0] == v || g[w][1] == v) && f(w) {
return true
}
}
return false
}
return f(0)
}