snake_ladder

c/snake_and_ladder.cpp

@@ -0,0 +1,72 @@
+//  snake and ladder problem
+#include "bits/stdc++.h"
+
+using namespace std;
+int32_t main()
+{
+  int ladders, snakes;
+  cin >> ladders;
+  map<int, int> lad;
+  map<int, int> snak;
+  for (int i = 0; i < ladders; i++)
+  {
+    int u, v;
+    cin >> u >> v;
+    lad[u] = v;
+  }
+  cin >> snakes;
+  for (int i = 0; i < snakes; i++)
+  {
+    int u, v;
+    cin >> u >> v;
+    snak[u] = v;
+  }
+  int moves = 0;
+  queue<int> q;
+  q.push(1);
+  bool found = false;
+  vector<int> vis(101, 0);
+  vis[1] = true;
+  while (!q.empty() and !found)
+  {
+    int sz = q.size();
+    while (sz--)
+    {
+      int t = q.front();
+      q.pop();
+      for (int die = 1; die <= 6; die++)
+      {
+        if (t + die == 100)
+          found = true;
+        if (t + die <= 100 and lad[t + die] and !vis[lad[t + die]])
+        {
+          vis[lad[t + die]] = true;
+          if (lad[t + die] == 100)
+          {
+            found = true;
+          }
+          q.push(lad[t + die]);
+        }
+        else if (t + die <= 100 and snak[t + die] and !vis[snak[t + die]])
+        {
+          vis[snak[t + die]] = true;
+          if (snak[t + die] == 100)
+            found = true;
+          q.push(snak[t + die]);
+        }
+        else if (t + die <= 100 and !vis[t + die] and !snak[t + die] and !lad[t + die])
+        {
+          vis[t + die] = true;
+          q.push(t + die);
+        }
+      }
+    }
+    moves++;
+  }
+  if (found)
+    cout << moves;
+  else
+  {
+    cout << -1;
+  }
+}