feat(bfs, backtracking): new problem formated

sliding-puzzle/src/ac.cpp

@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N = 6;
+unordered_set<string> games;
+queue<pair<string, int>> q;
+
+void addGame(int i, int j, string &s)
+{
+   swap(s[i], s[j]);
+   if (!games.count(s))
+      q.emplace(s, j);
+   games.insert(s);
+   swap(s[i], s[j]);
+}
+
+int bfs(string target)
+{
+   q.push({"123450", 5});
+   int depth = 0;
+   while (!q.empty())
+   {
+      int n = (int)q.size();
+      while (n--)
+      {
+         auto [s, zeroPos] = q.front();
+         q.pop();
+         if (s == target)
+            return depth;
+         int up = zeroPos - 3, down = zeroPos + 3, left = zeroPos - 1, right = zeroPos + 1;
+         if (up >= 0)
+            addGame(zeroPos, up, s);
+         if (down < N)
+            addGame(zeroPos, down, s);
+         if (left >= 0 && zeroPos != 3)
+            addGame(zeroPos, left, s); // 3 is the down left side
+         if (right < N && zeroPos != 2)
+            addGame(zeroPos, right, s); // 2 is the top right side
+      }
+
+      depth++;
+   }
+
+   return -1;
+}
+
+int main()
+{
+   vector<string> board(2);
+   for (int i = 0; i < 2; i++)
+   {
+      cin >> board[i];
+   }
+
+   cout << bfs((board[0] + board[1])) << endl;
+
+   return 0;
+}