救基友

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
const int INF = 1<<10;
const int N = 22;
const int Size = 999999;
using namespace std;
char b[N][N] ;
int vis[N][N][INF];
struct node
{
    int x,y,z,ans ;
}q[Size];
int n,m,T;
int mv[4][2] = {{1,0},{0,-1},{-1,0},{0,1}};
void BFS(int x ,int y)
{
    int s = 0 , e = 0  ;
    node f , t ;
    t.x = x ;
    t.y = y ;
    t.ans = 0 ;
    t.z = 0 ;
    q[e++] = t ;
    vis[t.x][t.y][t.z] = 1;
    while(s < e)
    {
        t = q[s++] ;
        if(b[t.x][t.y]=='^' && t.ans < T)
        {
                printf("%d\n", t.ans);
                return ;
        }
        for(int i = 0;i < 4;i++)
        {
            f.x = t.x + mv[i][0];
            f.y = t.y + mv[i][1];
			f.z = t.z;
            if(f.x >= 0 && f.x < n && f.y >= 0 && f.y < m && vis[f.x][f.y][f.z]==0)
            {
                if(b[f.x][f.y]=='@' || b[f.x][f.y]=='.' || b[f.x][f.y]=='^')
                {
                    f.ans = t.ans  + 1;
                    q[e++] = f ;
                    vis[f.x][f.y][f.z] = 1 ;
                }
                else if('a' <= b[f.x][f.y] && b[f.x][f.y] <='j' )
                {
                    int sum = 0,kk,xx;
                    f.ans  = t.ans  + 1;
                    xx = f.z;
                    kk = b[f.x][f.y] - 'a' + 1;
                    for(int ll = 0;ll<kk;ll++)
                    {
                        sum = xx % 2;
                        xx /= 2;
                    }
                    if(sum==0)
                        f.z += pow(2,(b[f.x][f.y]-'a'));

                     vis[f.x][f.y][f.z] = 1 ;
                    q[e++] = f ;
                }
                else if('A' <= b[f.x][f.y] && b[f.x][f.y] <='J' )
                {
                    int sum = 0,kk,xx;
                    f.ans  = t.ans  + 1;
                    xx = f.z;
                    kk = b[f.x][f.y] - 'A' + 1;
                    for(int ll = 0;ll<kk;ll++)
                    {
                        sum = xx % 2;
                        xx /= 2;
                    }
                    if(sum==1)
                    {
                        f.ans  = t.ans  + 1;
                    q[e++] = f ;
                    vis[f.x][f.y][f.z] = 1 ;
                    }
                }
            }
        }
    }
    printf("-1\n");
}
int main()
{
    while(~scanf("%d%d%d",&n,&m,&T))
    {
        int x,y;
        memset(vis,0,sizeof(vis));
         for(int i = 0 ; i < n ; i++)
            {
                scanf("%s%*c", b[i]);
            }
            for(int i = 0;i<n;i++)
            {
                 for(int j = 0;j < m;j++)
                {
                    if(b[i][j]=='@')
                    {
                        x = i;
                        y = j;
                        break;
                    }
                }
            }
       BFS(x,y);
    }
    return 0;
}