满脑子dp简直魔性

模拟题意bfs转移即可

#include
    
     #include
     
      #include
      
       using namespace std;const int N=200005;int s,t,d[N];bool v[N];queue
       
        q;inline void wk(int x,int y){    d[y]=d[x]+1;    if(!v[y])    {        v[y]=1;        q.push(y);    }}int main(){    scanf("%d%d",&s,&t);    for(int i=0;i<=200000;i++)        d[i]=1e9;    v[s]=1,d[s]=0,q.push(s);    while(!q.empty())    {        int u=q.front();        q.pop();        v[u]=0;        if(u*2<=200000&&d[u*2]>d[u]+1)            wk(u,u*2);        if(u+1<=200000&&d[u+1]>d[u]+1)            wk(u,u+1);        if(u-1>=0&&d[u-1]>d[u]+1)            wk(u,u-1);    }    printf("%d\n",d[t]);    return 0;}