AC Code

cses1193.cpp

@@ -0,0 +1,97 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+#define int long long
+const int maxN = 1e3 + 5;
+
+char a[maxN][maxN];
+int d[maxN][maxN];
+bool vis[maxN][maxN];
+int n, m, sx, sy, ex, ey;
+int moveX[] = {0, 0, 1, -1};
+int moveY[] = {1, -1, 0, 0};
+char moveChar[]={'R','L','D','U'};
+
+
+void bfs (int sx, int sy)
+{
+	for (int i = 1; i <= n; i++)
+	{
+		fill_n(d[i],m+1,0);
+		fill_n(vis[i],m+1,false);
+	}
+	queue<pair<int,int>>q;
+	q.push({sx, sy});
+	vis[sx][sy] = true;
+	while(!q.empty())
+	{
+		int x = q.front().first;
+		int y = q.front().second;
+		q.pop();
+		if (a[x][y] == 'B') return;
+		for (int i = 0; i < 4; i++)
+		{
+			int u = x + moveX[i];
+			int v = y + moveY[i];
+			if (u > n || u < 1) continue;
+			if (v > m || v < 1) continue;
+			if (a[u][v] == '#') continue;
+
+			if (!vis[u][v])
+			{
+				d[u][v] = d[x][y] + 1;
+				vis[u][v] = true;
+				a[u][v]=moveChar[i];
+				q.push({u,v});
+			}
+		}
+	}
+}
+
+signed main()
+{
+	cin >> n >> m;
+	for (int i = 1; i <= n; i++)
+	{
+		for (int j = 1; j <= m; j++)
+		{
+			cin >> a[i][j];
+			if (a[i][j] == 'A')
+			{
+				sx = i;
+				sy = j;
+			}
+			if (a[i][j] == 'B')
+			{
+				ex = i;
+				ey = j;
+			}
+		}
+	}
+	bfs(sx, sy);
+	if (d[ex][ey] > 0) { cout << "YES\n";
+	cout << d[ex][ey] << '\n';
+	string ans = "";
+	int c = ex;
+	int currj = ey;
+	while(!(c == sx && currj == sy)){
+        ans += a[c][currj];
+        switch(a[c][currj]){
+            case 'D':
+                c--;
+                break;
+            case 'U':
+                c++;
+                break;
+            case 'R':
+                currj--;
+                break;
+            case 'L':
+                currj++;
+                break;
+        }
+    }
+    reverse(ans.begin(),ans.end());
+    cout <<ans;}
+    else cout << "NO";
+}