BOJ 314 Good boy, laiyifa! [最短路spfa]

#include<iostream>
#include<fstream>
#include<map>
#include<vector>
#include<string>
#include<memory.h>
#include<cmath>
#include<algorithm>
#include<queue>
#define Min(a,b) (a<b?a:b)
#define Max(a,b) (a>b?a:b)
#define Abs(a) (a>0?(a):-(a))
#define llong long long int
using namespace std;
const int N=1005,inf=0x7fffffff;
int n,m;
int mat

;
int dis
;
bool vis
;
int spfa(int s,int t)
{
for(int i =1;i<=n;i++)
dis[i]=inf;
dis[s]=0;
queue<int> que;
memset(vis,0,sizeof(vis));
vis[s]=true;
que.push(s);
while(!que.empty())
{
int now=que.front();
que.pop();
vis[now]=false;
for(int i=1;i<=n;i++)
{
if(mat[now][i] && dis[now]!=inf && dis[i] > dis[now]+mat[now][i])
{
dis[i]=dis[now]+mat[now][i];
if(!vis[i])
{
vis[i]=true;
que.push(i);
}
}
}
}
return dis[t];
}
int main()
{
while(scanf("%d%d",&n,&m)!=EOF)
{
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
{
scanf("%d",mat[i]+j);
}
int ans=0,ret=0;
ret=spfa(1,n);
if(ret!=inf)
ans+=ret;
else
{
printf("-1\n");
continue;
}
ret=spfa(n,1);
if(ret!=inf)
ans+=ret;
else
{
printf("-1\n");
continue;
}
if(ans<=m)
{
printf("%d\n",ans);
}
else
{
printf("-1\n");
}

}
return 0;
}