delete pics to save space

history_source/信息学奥赛一本通/2.8.6.cpp

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+#include<cstdio>
+#include<queue>
+using namespace std;
+int ans[133334]={0},n,k,x;
+int main()
+{
+	queue<int>q;
+	scanf("%d%d",&n,&k);
+	q.push(n);
+	ans[n]=1;
+	do
+	{
+		x=q.front();
+		if(x>0&&ans[x-1]==0)
+		{
+			ans[x-1]=ans[x]+1;
+			q.push(x-1);
+		}
+		if(x<k&&ans[x+1]==0)
+		{
+			ans[x+1]=ans[x]+1;
+			q.push(x+1);
+		}
+		if(x*3<=k*2&&ans[x*2]==0)
+		{
+			ans[x*2]=ans[x]+1;
+			q.push(x*2);
+		}
+		q.pop();
+	}
+	while(ans[k]==0);
+	printf("%d\n",ans[k]-1);
+	return 0;
+}