关于o2

#include<bits/stdc++.h>
using namespace std;
int dp[100005],vis[100005];
int pii[16];
queue<int> q;
char gc(){
	char ch=getchar();
	while(ch!='0'&&ch!='1') ch=getchar();
	return ch;
}
int frm,to;
main(){
	pii[0]=1;
	for(int i=1;i<=16;i++) pii[i]=pii[i-1]<<1;
	for(int i=1,u;i<=16;i++) u=gc()-'0',frm+=u*pii[i-1];
	q.push(frm);
	for(int i=1,u;i<=16;i++) u=gc()-'0',to+=u*pii[i-1];
	while(!q.empty()){
		int x=q.front();q.pop();
		if(x==to){
			printf("%d",dp[x]);
			return 0;
		}
		for(int i=1;i<=16;i++){
			if(!(x&pii[i-1])) continue;
			for(int j=1;j<=16;j++){
				if(x&pii[j-1]) continue;
				if(!vis[x-pii[i-1]+pii[j-1]]&&(j==i+4||j==i-4||(j==i-1&&i%4!=1)||(j==i+1&&i%4))){
					q.push(x-pii[i-1]+pii[j-1]);
					dp[x-pii[i-1]+pii[j-1]]=dp[x]+1;
					vis[x-pii[i-1]+pii[j-1]]=1;
				}
			}
		}
	}
}