update

poj/3278.catch-that-cow/main.cc

@@ -0,0 +1,45 @@
+#include <cstdio>
+#include <cstring>
+#include <queue>
+
+using namespace std;
+
+const int L = 200001;
+
+bool set[L];
+
+int main() {
+  int N, K;
+  scanf("%d %d", &N, &K);
+  queue<int> q;
+  q.push(N);
+  memset(set, 0, sizeof(set));
+  set[N] = true;
+  int s = 1, t = 0;
+  while (s != 0) {
+    int n = q.front();
+    q.pop();
+    s--;
+    if (n == K) break;
+    if (n < K) {
+      if (!set[2 * n]) {
+        q.push(2 * n);
+        set[2 * n] = true;
+      }
+      if (!set[n + 1]) {
+        q.push(n + 1);
+        set[n + 1] = true;
+      }
+    }
+    if (0 < n && !set[n - 1]) {
+      q.push(n - 1);
+      set[n - 1] = true;
+    }
+    if (s == 0) {
+      s = q.size();
+      t++;
+    }
+  }
+  printf("%d\n", t);
+  return 0;
+}