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| #include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
const int MAXN = 9 + 5;
const int MAXL = 500 + 10;
const int MAXI = MAXL * MAXL;
const int MAXM = 4 * MAXI;
const int INF = 0x3f3f3f3f;
const int NextX[4]= {- 1, 0, 1, 0}, NextY[4]= {0, - 1, 0, 1};
struct LinkedForwardStar {
int to;
int next;
} ;
LinkedForwardStar Link[MAXM];
int Head[MAXI]= {0};
int size = 0;
void Insert (int u, int v) {
Link[++ size].to = v;
Link[size].next = Head[u];
Head[u] = size;
}
int N, R, C;
char Map[MAXL][MAXL];
int encode (int x, int y) {
return (x - 1) * C + y;
}
int fto[MAXL][MAXL][4]= {0};
bool vis[MAXL][MAXL][4]= {false};
int move (int x, int y, int k) {
if (vis[x][y][k])
return fto[x][y][k] = - 1;
if (fto[x][y][k])
return fto[x][y][k];
int tx = x + NextX[k], ty = y + NextY[k];
vis[x][y][k] = true;
if (Map[tx][ty] == 'x')
fto[x][y][k] = encode (x, y);
else if (Map[tx][ty] == 'A')
fto[x][y][k] = move (tx, ty, (k + 1) % 4);
else if (Map[tx][ty] == 'C')
fto[x][y][k] = move (tx, ty, (k + 3) % 4);
else
fto[x][y][k] = move (tx, ty, k);
vis[x][y][k] = false;
return fto[x][y][k];
}
int f[MAXN][MAXN][MAXI];
queue<int> que1, que2;
int inque[MAXI]= {0};
int buck[MAXI]= {0};
int save[MAXI];
int total = 0;
void fsort (int l, int r) {
total = 0;
int limit = 0;
for (int i = 1; i <= R * C; i ++)
if (f[l][r][i] < INF)
limit = max (limit, f[l][r][i]), total ++;
for (int i = 1; i <= limit; i ++)
buck[i] = 0;
for (int i = 1; i <= R * C; i ++)
if (f[l][r][i] < INF)
buck[f[l][r][i]] ++;
for (int i = 1; i <= limit; i ++)
buck[i] += buck[i - 1];
for (int i = R * C; i >= 1; i --)
if (f[l][r][i] < INF)
save[buck[f[l][r][i]] --] = i;
}
void SPFA (int l, int r) {
fsort (l, r);
for (int i = 1; i <= total; i ++)
que1.push(save[i]), inque[save[i]] = 1;
while (! que1.empty() || ! que2.empty()) {
int u;
int f1 = ! que1.empty() ? que1.front() : INF;
int f2 = ! que2.empty() ? que2.front() : INF;
f1 < f2 ? (u = f1, que1.pop()) : (u = f2, que2.pop());
inque[u] = 0;
for (int i = Head[u]; i; i = Link[i].next) {
int v = Link[i].to;
if (f[l][r][u] + 1 < f[l][r][v]) {
f[l][r][v] = f[l][r][u] + 1;
if (! inque[v])
que2.push(v), inque[v] = 1;
}
}
}
}
int main () {
scanf ("%d%d%d", & N, & C, & R);
for (int i = 1; i <= R; i ++)
scanf ("%s", Map[i] + 1);
for (int i = 1; i <= R; i ++)
Map[i][0] = Map[i][C + 1] = 'x';
for (int j = 1; j <= C; j ++)
Map[0][j] = Map[R + 1][j] = 'x';
for (int i = 1; i <= R; i ++)
for (int j = 1; j <= C; j ++) {
if (Map[i][j] == 'x')
continue;
for (int k = 0; k < 4; k ++) {
move (i, j, k);
if ((~ fto[i][j][k]) && fto[i][j][k] != encode (i, j))
Insert (encode (i, j), fto[i][j][k]);
}
}
memset (f, 0x3f, sizeof (f));
for (int i = 1; i <= R; i ++)
for (int j = 1; j <= C; j ++)
if (isdigit (Map[i][j]))
f[Map[i][j] - '0'][Map[i][j] - '0'][encode (i, j)] = 0;
for (int len = 1; len <= N; len ++)
for (int l = 1; l <= N - len + 1; l ++) {
int r = l + len - 1;
for (int i = 1; i <= R * C; i ++) {
for (int k = l; k < r; k ++)
f[l][r][i] = min (f[l][r][i], f[l][k][i] + f[k + 1][r][i]);
}
SPFA (l, r);
}
int ans = INF;
for (int i = 1; i <= R * C; i ++)
ans = min (ans, f[1][N][i]);
printf ("%d\n", ans == INF ? - 1 : ans);
return 0;
}
|
