Borg maze (bfs+ minimum spanning tree) (problem solving report)

Borg Maze

The Borg is an immensely powerful race of enhanced humanoids from the delta quadrant of the galaxy. The Borg collective is the term used to describe the group consciousness of the Borg civilization. Each Borg individual is linked to the collective by a sophisticated subspace network that insures each member is given constant supervision and guidance.

Your task is to help the Borg (yes, really) by developing a program which helps the Borg to estimate the minimal cost of scanning a maze for the assimilation of aliens hiding in the maze, by moving in north, west, east, and south steps. The tricky thing is that the beginning of the search is conducted by a large group of over 100 individuals. Whenever an alien is assimilated, or at the beginning of the search, the group may split in two or more groups (but their consciousness is still collective.). The cost of searching a maze is definied as the total distance covered by all the groups involved in the search together. That is, if the original group walks five steps, then splits into two groups each walking three steps, the total distance is 11=5+3+3.
Input
On the first line of input there is one integer, N <= 50, giving the number of test cases in the input. Each test case starts with a line containg two integers x, y such that 1 <= x,y <= 50. After this, y lines follow, each which x characters. For each character, a space ‘’ stands for an open space, a hash mark #’’ stands for an obstructing wall, the capital letter A’’ stand for an alien, and the capital letter S’’ stands for the start of the search. The perimeter of the maze is always closed, i.e., there is no way to get out from the coordinate of the ``S’’. At most 100 aliens are present in the maze, and everyone is reachable.
Output
For every test case, output one line containing the minimal cost of a succesful search of the maze leaving no aliens alive.

Sample Input
2
6 5
##### 
#A#A##
# # A#
#S ##
##### 
7 7
#####  
#AAA###
# A#
# S ###
#     #
#AAA###
#####  


Sample Output
8
11

Have you guys explained , Why eliminate line breaks here gets(g[0]); and getchar() no way , look for bug For a long time , Just found it ,qaq

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <queue>
#include <map>
using namespace std;
int const INF=0x3f3f3f3f;
char g[100][100];
int n,m,tol,k;
int a[100][100],cost[1100][1100],t[1000][1000];
int mo[][2]={
    {
    -1,0},{
    1,0},{
    0,1},{
    0,-1}};
bool vis[1100];
int dis[1100];

void bfs(int sx,int sy)
{
    
    queue<pair<int,int> >q;
    while(!q.empty())
        q.pop();  // Clear queue ;pop Pop up the element in the column header ;
    memset(t,-1,sizeof(t));//t[][] Mark whether to walk , And record the distance ;
    t[sx][sy]=0;
    q.push(make_pair(sx,sy));//push Push the element into the tail 
    while(!q.empty())
    {
    
        pair<int,int> now=q.front();// Visit team leader elements 
        q.pop();
        if(a[now.first][now.second]!=-1)// encounter A or S character , Update distance cost;
          {
    
              cost[a[sx][sy]][a[now.first][now.second]]=t[now.first][now.second];

          }
        for(int i=0;i<4;i++)
            {
    
                int tx=now.first+mo[i][0];// Up, down, left and right of the current point ;
                int ty=now.second+mo[i][1];
                if(g[tx][ty]=='#'||t[tx][ty]!=-1)//t[][] Mark whether to walk ;
                    continue;
                else
                {
    
                    t[tx][ty]=t[now.first][now.second]+1;// Record the distance ;
                    q.push(make_pair(tx,ty));
                }
            }
    }
}
int Prim(int tol)// It's familiar again prim Algorithm ;
{
    
    int ans=0,p;
    memset(vis,0,sizeof(vis));
    vis[0]=1;
    for(int i=1;i<tol;i++)
        dis[i]=cost[0][i];
    for(int i=1;i<tol;i++)
    {
    
        int minn=INF;
         p=-1;
        for(int j=0;j<tol;j++)
        {
    
            if(vis[j]==0&&minn>dis[j])
            {
    
                p=j;
                minn=dis[j];
            }
        }
        if(minn==INF)
            return -1;
        vis[p]=1;
        ans+=minn;
        for(int j=0;j<tol;j++)
        {
    
            if(vis[j]==0&&dis[j]>cost[p][j])
                dis[j]=cost[p][j];
        }
    }
    return ans;
}
int main()
{
    
    int k;
scanf("%d",&k);
  while(k--)
  {
    
      scanf("%d%d",&m,&n);
      gets(g[0]);
      tol=0;
      memset(a,-1,sizeof(a));
      for(int i=0;i<n;i++)
      {
    
          gets(g[i]);// The input character ,gets There must be clear spaces ;
            for(int j=0;j<m;j++)
          {
    
              if(g[i][j]=='A'||g[i][j]=='S')
                a[i][j]=tol++;// use a Array tags A and S,( From the first few A/S To the first few A/S);
                            // A total of tol individual A and S, Be careful tol from 0 Start ;
          }
      }
      for(int i=0;i<n;i++)
      {
    
          for(int j=0;j<m;j++)
          {
    
              if(a[i][j]!=-1)// Let each point be a starting point ;
                bfs(i,j);
          }
      }
      printf("%d\n",Prim(tol));

  }
    return 0;
}