添加 problem 864

Author: halfrost

Algorithms/0864. Shortest Path to Get All Keys/864. Shortest Path to Get All Keys.go

@@ -0,0 +1,168 @@
+package leetcode
+
+import (
+	"math"
+	"strings"
+)
+
+// 解法一 BFS，利用状态压缩来过滤筛选状态
+func shortestPathAllKeys(grid []string) int {
+	if len(grid) == 0 {
+		return 0
+	}
+	board, visited, startx, starty, res, fullKeys := make([][]byte, len(grid)), make([][][]bool, len(grid)), 0, 0, 0, 0
+	for i := 0; i < len(grid); i++ {
+		board[i] = make([]byte, len(grid[0]))
+	}
+	for i, g := range grid {
+		board[i] = []byte(g)
+		for _, v := range g {
+			if v == 'a' || v == 'b' || v == 'c' || v == 'd' || v == 'e' || v == 'f' {
+				fullKeys |= (1 << uint(v-'a'))
+			}
+		}
+		if strings.Contains(g, "@") {
+			startx, starty = i, strings.Index(g, "@")
+		}
+	}
+	for i := 0; i < len(visited); i++ {
+		visited[i] = make([][]bool, len(board[0]))
+	}
+	for i := 0; i < len(board); i++ {
+		for j := 0; j < len(board[0]); j++ {
+			visited[i][j] = make([]bool, 64)
+		}
+	}
+	queue := []int{}
+	queue = append(queue, (starty<<16)|(startx<<8))
+	visited[startx][starty][0] = true
+	for len(queue) != 0 {
+		qLen := len(queue)
+		for i := 0; i < qLen; i++ {
+			state := queue[0]
+			queue = queue[1:]
+			starty, startx = state>>16, (state>>8)&0xFF
+			keys := state & 0xFF
+			if keys == fullKeys {
+				return res
+			}
+			for i := 0; i < 4; i++ {
+				newState := keys
+				nx := startx + dir[i][0]
+				ny := starty + dir[i][1]
+				if !isInBoard(board, nx, ny) {
+					continue
+				}
+				if board[nx][ny] == '#' {
+					continue
+				}
+				flag, canThroughLock := keys&(1<<(board[nx][ny]-'A')), false
+				if flag != 0 {
+					canThroughLock = true
+				}
+				if isLock(board, nx, ny) && !canThroughLock {
+					continue
+				}
+				if isKey(board, nx, ny) {
+					newState |= (1 << (board[nx][ny] - 'a'))
+				}
+				if visited[nx][ny][newState] {
+					continue
+				}
+				queue = append(queue, (ny<<16)|(nx<<8)|newState)
+				visited[nx][ny][newState] = true
+			}
+		}
+		res++
+	}
+	return -1
+}
+
+// 解法二 DFS，但是超时了，剪枝条件不够强
+func shortestPathAllKeys1(grid []string) int {
+	if len(grid) == 0 {
+		return 0
+	}
+	board, visited, startx, starty, res, fullKeys := make([][]byte, len(grid)), make([][][]bool, len(grid)), 0, 0, math.MaxInt64, 0
+	for i := 0; i < len(grid); i++ {
+		board[i] = make([]byte, len(grid[0]))
+	}
+	for i, g := range grid {
+		board[i] = []byte(g)
+		for _, v := range g {
+			if v == 'a' || v == 'b' || v == 'c' || v == 'd' || v == 'e' || v == 'f' {
+				fullKeys |= (1 << uint(v-'a'))
+			}
+		}
+		if strings.Contains(g, "@") {
+			startx, starty = i, strings.Index(g, "@")
+		}
+	}
+	for i := 0; i < len(visited); i++ {
+		visited[i] = make([][]bool, len(board[0]))
+	}
+	for i := 0; i < len(board); i++ {
+		for j := 0; j < len(board[0]); j++ {
+			visited[i][j] = make([]bool, 64)
+		}
+	}
+	searchKeys(board, &visited, fullKeys, 0, (starty<<16)|(startx<<8), &res, []int{})
+	if res == math.MaxInt64 {
+		return -1
+	}
+	return res - 1
+}
+
+func searchKeys(board [][]byte, visited *[][][]bool, fullKeys, step, state int, res *int, path []int) {
+	y, x := state>>16, (state>>8)&0xFF
+	keys := state & 0xFF
+
+	if keys == fullKeys {
+		*res = min(*res, step)
+		return
+	}
+
+	flag, canThroughLock := keys&(1<<(board[x][y]-'A')), false
+	if flag != 0 {
+		canThroughLock = true
+	}
+	newState := keys
+	//fmt.Printf("x = %v y = %v fullKeys = %v keys = %v step = %v res = %v path = %v state = %v\n", x, y, fullKeys, keys, step, *res, path, state)
+	if (board[x][y] != '#' && !isLock(board, x, y)) || (isLock(board, x, y) && canThroughLock) {
+		if isKey(board, x, y) {
+			newState |= (1 << uint(board[x][y]-'a'))
+		}
+		(*visited)[x][y][newState] = true
+		path = append(path, x)
+		path = append(path, y)
+
+		for i := 0; i < 4; i++ {
+			nx := x + dir[i][0]
+			ny := y + dir[i][1]
+			if isInBoard(board, nx, ny) && !(*visited)[nx][ny][newState] {
+				searchKeys(board, visited, fullKeys, step+1, (ny<<16)|(nx<<8)|newState, res, path)
+			}
+		}
+		(*visited)[x][y][keys] = false
+		path = path[:len(path)-1]
+		path = path[:len(path)-1]
+	}
+}
+
+func isLock(board [][]byte, x, y int) bool {
+	if (board[x][y] == 'A') || (board[x][y] == 'B') ||
+		(board[x][y] == 'C') || (board[x][y] == 'D') ||
+		(board[x][y] == 'E') || (board[x][y] == 'F') {
+		return true
+	}
+	return false
+}
+
+func isKey(board [][]byte, x, y int) bool {
+	if (board[x][y] == 'a') || (board[x][y] == 'b') ||
+		(board[x][y] == 'c') || (board[x][y] == 'd') ||
+		(board[x][y] == 'e') || (board[x][y] == 'f') {
+		return true
+	}
+	return false
+}

Algorithms/0864. Shortest Path to Get All Keys/864. Shortest Path to Get All Keys_test.go

@@ -0,0 +1,77 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question864 struct {
+	para864
+	ans864
+}
+
+// para 是参数
+// one 代表第一个参数
+type para864 struct {
+	one []string
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans864 struct {
+	one int
+}
+
+func Test_Problem864(t *testing.T) {
+
+	qs := []question864{
+
+		question864{
+			para864{[]string{".##..##..B", "##...#...#", "..##..#...", ".#..#b...#", "#.##.a.###", ".#....#...", ".##..#.#..", ".....###@.", "..........", ".........A"}},
+			ans864{11},
+		},
+
+		question864{
+			para864{[]string{"Dd#b@", ".fE.e", "##.B.", "#.cA.", "aF.#C"}},
+			ans864{14},
+		},
+
+		question864{
+			para864{[]string{"@...a", ".###A", "b.BCc"}},
+			ans864{10},
+		},
+
+		question864{
+			para864{[]string{"@Aa"}},
+			ans864{-1},
+		},
+
+		question864{
+			para864{[]string{"b", "A", "a", "@", "B"}},
+			ans864{3},
+		},
+
+		question864{
+			para864{[]string{"@.a.#", "#####", "b.A.B"}},
+			ans864{-1},
+		},
+
+		question864{
+			para864{[]string{"@.a.#", "###.#", "b.A.B"}},
+			ans864{8},
+		},
+
+		question864{
+			para864{[]string{"@..aA", "..B#.", "....b"}},
+			ans864{6},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 864------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans864, q.para864
+		fmt.Printf("【input】:%v       【output】:%v\n", p, shortestPathAllKeys(p.one))
+	}
+	fmt.Printf("\n\n\n")
+}