这里是源代码

#include<bits/stdc++.h>
using namespace std;
#define PII pair<int,int>
inline int read(){
	int sum=0,h=1;
	char ch=getchar();
	while(!isdigit(ch)){if(ch=='-') h=-1;ch=getchar();}
	while(isdigit(ch)){sum=sum*10+ch-'0';ch=getchar();}
	return sum*h;
}
int dir[2]={1,-1};
int n,x,y;
queue<PII> q;
inline void bfs(){
	while(!q.empty()){
		PII top=q.front();q.pop();
		int ax=top.first,cnt=top.second;
		if(ax==y){
			cout<<cnt<<endl;
			return;
		}
		for(register int i=0;i<=2;++i){
			if(i==2){
				int bx=ax*2;
				q.push({bx,cnt+1});
				break;
			}
			int bx=ax+dir[i];
			if(bx<=0) continue;
			q.push({bx,cnt+1});
		}
	}
	return;
}
int main(){
	n=read();
	for(register int i=0;i<n;++i){
		x=read(),y=read();
		q.push({x,0});
		bfs();
	}
	return 0;
}

求助大佬，指明原因。