#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
const int N = 1e3 + 10;
int g[N][N];
bool st[N][N][20];
int dis[N][N][20];
int n, m, k;
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};
bool check(int x, int y) {
return x >= 0 && x < n && y >= 0 && y < m;
}
int bfs() {
for(int i = 0; i < n; i ++) {
for(int j = 0; j < m; j ++) {
for(int p = 0; p < k; p ++) {
dis[i][j][p] = INF;
}
}
}
queue<array<int,3>>q;
q.push({0, 0, 1});
dis[0][0][1] = 1;
st[0][0][1] = true;
while(q.size()){
auto t = q.front();
q.pop();
int x = t[0], y = t[1], cnt = t[2];
int d = dis[x][y][cnt];
for(int i = 0; i < 4; i ++) {
int nx = x + dx[i];
int ny = y + dy[i];
int nc = (d / k) % 2;
if(check(nx, ny) && g[nx][ny] == nc && !st[nx][ny][(d + 1) % k]) {
st[nx][ny][(d + 1) % k] = true;
q.push({nx, ny, (d + 1) % k});
dis[nx][ny][(d + 1) % k] = d + 1;
}
}
}
int minv = INF;
for(int i = 0; i < k; i ++) {
minv = min(minv, dis[n - 1][m - 1][i]);
}
return minv;
}
void solve(){
cin >> n >> m >> k;
for(int i = 0; i < n; i ++) {
string s; cin >> s;
for(int j = 0; j < m; j ++) {
g[i][j] = (s[j] != 'A');
}
}
int res = bfs();
if(res == INF){
cout << -1 << endl;
}else{
cout << res - 1 << endl;
}
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
while(t--){
solve();
}
return 0;
}
2、python3
python复制代码
from collections import deque
INF = 0x3f3f3f3f
N = 1010
n, m, k = map(int, input().split())
st = [[[False] * 20 for _ in range(N)] for _ in range(N)]
dis = [[[INF] * 20 for _ in range(N)] for _ in range(N)]
g = [[0] * N for _ in range(N)]
dx = [-1, 0, 1, 0]
dy = [0, 1, 0, -1]
def check(x, y):
return x >= 0 and x < n and y >= 0 and y < m
def bfs():
q = deque([(0, 0, 1)])
dis[0][0][1] = 1
st[0][0][1] = True
while q:
x, y, cnt = q[0]
q.popleft()
d = dis[x][y][cnt]
for i in range(4):
nx = x + dx[i]
ny = y + dy[i]
nc = (d // k) % 2
if check(nx, ny) and g[nx][ny] == nc and st[nx][ny][(d + 1) % k] == False:
st[nx][ny][(d + 1) % k] = True
q.append((nx, ny, (d + 1) % k))
dis[nx][ny][(d + 1) % k] = d + 1
minv = INF
for i in range(k):
minv = min(minv, dis[n - 1][m - 1][i])
return minv
for i in range(n):
s = input()
for j in range(m):
if s[j] != 'A':
g[i][j] = 1
else:
g[i][j] = 0
res = bfs()
if res == INF:
print(-1)
else:
print(res - 1)
3、Java
java复制代码
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
public class ABRoad {
public static final int INF = 0x3f3f3f3f;
public static int[] dx = new int[]{-1, 0, 1, 0};
public static int[] dy = new int[]{0, 1, 0, -1};
public static int n, m, k;
public static int[][] g;
public static boolean[][][] st;
public static int[][][] dis;
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
n = sc.nextInt();
m = sc.nextInt();
k = sc.nextInt();
g = new int[n + 10][m + 10];
st = new boolean[n + 10][m + 10][k + 10];
dis = new int[n + 10][m + 10][k + 10];
for(int i = 0; i < n; i ++ ) {
String s;
s = sc.next();
for(int j = 0; j < m; j ++) {
if(s.charAt(j) != 'A')
g[i][j] = 1;
else
g[i][j] = 0;
}
}
int res = bfs();
if(res == INF)
System.out.println(-1);
else
System.out.println(res - 1);
}
private static int bfs() {
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
for (int p = 0; p < k; p++) {
dis[i][j][p] = INF;
}
}
}
Queue<int[]> q = new LinkedList<>();
q.add(new int[]{0, 0, 1});
dis[0][0][1] = 1;
st[0][0][1] = true;
while (!q.isEmpty()) {
int[] t = q.poll();
int x = t[0], y = t[1], cnt = t[2];
int d = dis[x][y][cnt];
for (int i = 0; i < 4; i++) {
int nx = x + dx[i];
int ny = y + dy[i];
int nc = (d / k) % 2;
if (check(nx, ny) && g[nx][ny] == nc && !st[nx][ny][(d + 1) % k]) {
st[nx][ny][(d + 1) % k] = true;
q.add(new int[]{nx, ny, (d + 1) % k});
dis[nx][ny][(d + 1) % k] = d + 1;
}
}
}
int minv = INF;
for(int i = 0; i < k; i ++) {
minv = Math.min(minv, dis[n - 1][m - 1][i]);
}
return minv;
}
private static boolean check(int x, int y) {
return x >= 0 && x < n && y >= 0 && y < m;
}
}
