蒟蒻14分求调（WA+TLE+MLE）

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=305,W=5;
char mp[N][N],c;
bool v[N][N];
int n,m,ans;
int mx[W]={1,0,0,-1};
int my[W]={0,1,-1,0};
struct node
{
	int x,y,step;
};
node now,tmp;
queue<node>q;
int bfs()
{
	while(!q.empty())
	{
		now=q.front();
		q.pop();
		if(mp[now.x][now.y]=='=') return now.step;
		if(mp[now.x][now.y]>='A' and mp[now.x][now.y]<='Z')
		{
			bool flag=0;
			c=mp[now.x][now.y];
			for(int i=1;i<=n;i++)
			{
				for(int j=1;j<=m;j++)
				{
					if(mp[i][j]==c and i!=now.x and j!=now.y)
					{
						tmp.x=i,tmp.y=j,tmp.step=now.step;
						q.push(tmp);
						flag=1;
						break;
					}
				}
				if(flag) break;
			}
		}
		for(int i=0;i<4;i++)
		{
			int nx=now.x+mx[i],ny=now.y+my[i];
			if(nx<1 or nx>n or ny<1 or ny>m) continue;
			if(mp[nx][ny]!='#' and !v[nx][ny])
			{
				tmp.x=nx,tmp.y=ny,tmp.step=now.step+1;
				v[now.x][now.y]=1;
				q.push(tmp);
			}
		}
	}
}
signed main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			cin>>mp[i][j];
			if(mp[i][j]=='@') now.x=i,now.y=j;
		}
	}
	now.step=0;
	q.push(now);
	ans=bfs();
	cout<<ans<<'\n';
	
	
	return 0;
}