init

3L.py

@@ -0,0 +1,70 @@
+import sys
+
+data = sys.stdin.read().split()
+if not data:
+    exit()
+n = int(data[0])
+m = int(data[1])
+ans = []
+for i in range(n):
+    ans.extend(list(data[2 + i]))
+q = [0] * (n * m)
+head = 0
+tail = 0
+for c in range(m):
+    if ans[c] == '.':
+        ans[c] = '^'
+        q[tail] = c
+        tail += 1
+for c in range(m):
+    pos = (n - 1) * m + c
+    if ans[pos] == '.':
+        ans[pos] = 'v'
+        q[tail] = pos
+        tail += 1
+for r in range(n):
+    pos = r * m
+    if ans[pos] == '.':
+        ans[pos] = '<'
+        q[tail] = pos
+        tail += 1
+for r in range(n):
+    pos = r * m + (m - 1)
+    if ans[pos] == '.':
+        ans[pos] = '>'
+        q[tail] = pos
+        tail += 1
+while head < tail:
+    pos = q[head]
+    head += 1    
+    r = pos // m
+    c = pos % m
+    if r > 0:
+        npos = pos - m
+        if ans[npos] == '.':
+            ans[npos] = 'v'
+            q[tail] = npos
+            tail += 1
+    if r < n - 1:
+        npos = pos + m
+        if ans[npos] == '.':
+            ans[npos] = '^'
+            q[tail] = npos
+            tail += 1
+    if c > 0:
+        npos = pos - 1
+        if ans[npos] == '.':
+            ans[npos] = '>'
+            q[tail] = npos
+            tail += 1
+    if c < m - 1:
+        npos = pos + 1
+        if ans[npos] == '.':
+            ans[npos] = '<'
+            q[tail] = npos
+            tail += 1
+
+out = []
+for r in range(n):
+    out.append("".join(ans[r * m : (r + 1) * m]))
+print("\n".join(out))