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2 years ago
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> PII;
/*
353*5=15
4*6=24
广:(n+1)*(m+1)
*/
const int N = 510 * 510;
const int M = 4 * N; // 1个格子里面有4条边分别为 a->b,b->a,c->d,d->c
const int INF = 0X3f3f3f3f;
int n, m;
int h[N], e[M], w[M], ne[M], idx;
int dist[N];
bool st[N];
void add(int a, int b, int c) {
e[idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx++;
}
int getNum(int x, int y) {
/*
* 0,1,2,3,4,...,m
* 1,2,3,4,...,m
m+1
广 = (01)* +
*/
return x * (m + 1) + y; //按点看共m+1列
}
int dijkstra() {
//初始化最短距离
memset(dist, 0x3f, sizeof dist);
dist[0] = 0; // 0号点的最短距离是0
// greater<>()小顶层堆
priority_queue<PII, vector<PII>, greater<PII>> q;
q.emplace(0, 0); //注意:先是距离后是序号之所以这样设计是因为小顶堆的排序是默认安排PII的第一维x进行由小到大
while (q.size()) {
auto t = q.top();
q.pop();
int u = t.second, distance = t.first;
//如果已经走过,不需要再尝试
if (st[u]) continue;
//标识走过
st[u] = true;
//枚举每个出边
for (int i = h[u]; ~i; i = ne[i]) {
int j = e[i];
if (dist[j] > distance + w[i]) { //在原距离distanc基础上再走w[i]后可以到达j,如果这样走近则更新dist[j]
dist[j] = distance + w[i];
q.emplace(dist[j], j); //将j加入队列继续扩展
}
}
}
//计算最后一个坐标位置对应的节点,它离起点的最短距离是多少
return dist[getNum(n, m)];
}
signed main() {
//加快读入
cin.tie(0), ios::sync_with_stdio(false);
int T;
cin >> T;
while (T--) {
//还原是否走过的状态st=false
memset(st, false, sizeof st);
//多组测试数据,清空邻接表
memset(h, -1, sizeof h);
idx = 0;
// n行m列
cin >> n >> m;
//读入数据+建图
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
char op;
cin >> op;
//现在读入的是当前(i,j)坐标的格子中操作符
/*
(0,0) (0,1) (i-1,j-1) (i-1,j)
(1,1) => (i,j)
(1,0) (1,1) (i,j-1) (i,j)
*/
int a = getNum(i - 1, j - 1);
int b = getNum(i, j);
int c = getNum(i, j - 1);
int d = getNum(i - 1, j);
// Q:为什么权值定义的是 /:1 \:0 呢?
// A:因为我们描述的是 a->b 的边:
// 如果a->b之间有边就是左上角到右下角有边, \ , 权值为0.
// 如果a->b之间无边就是右上角到左下角有边, / , 此时需要把它转过来权值为1.
int w = op == '/' ? 1 : 0;
add(a, b, w), add(b, a, w); //无向图,双向建边
add(c, d, !w), add(d, c, !w); //取反也建边模拟01边权的无向图
}
}
//求最短路
int res = dijkstra(); // dijkstra可以处理非负权边的图
if (res == INF)
puts("NO SOLUTION");
else
printf("%d\n", res);
}
return 0;
}