4318. 最短路径

https://www.acwing.com/problem/content/submission/code_detail/12517850/

AcWing/4318/4318.cpp

@@ -0,0 +1,47 @@
+#include <iostream>
+#include <map>
+#include <string>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int to[5][2] = {{0, 0}, {0, -1}, {0, 1}, {-1, 0}, {1, 0}};
+
+int x, y;
+std::string s;
+std::map<int, std::map<int, bool>> vis;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> s;
+    vis[x][y] = true;
+    for (char c : s) {
+        int xx = 0, yy = 0;
+        if (c == 'U') {
+            y--;
+            yy--;
+        } else if (c == 'D') {
+            y++;
+            yy++;
+        } else if (c == 'L') {
+            x--;
+            xx--;
+        } else if (c == 'R') {
+            x++;
+            xx++;
+        }
+
+        if (vis[x][y]) {
+            cout << "NO" << endl;
+            exit(0);
+        }
+
+        vis[x][y] = true;
+        for (int i = 1; i <= 4; i++) {
+            vis[x + to[i][0] - xx][y + to[i][1] - yy] = true;
+        }
+    }
+    cout << "YES" << endl;
+    return 0;
+}