OJ-Problems-Source/HDOJ/4370_autoAC.cpp

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#include<stdio.h>
#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
const int INF=0x3f3f3f3f;
const int MAXN=330;
int cost[MAXN][MAXN];
int dist[MAXN];
int que[MAXN];
bool vis[MAXN];
void SPFA(int start,int n)
{
int front=0,rear=0;
for(int v=1;v<=n;v++)
{
if(v==start)
{
dist[v]=INF;
vis[v]=false;
}
else if(cost[start][v]!=INF)
{
dist[v]=cost[start][v];
que[rear++]=v;
vis[v]=true;
}
else
{
dist[v]=INF;
vis[v]=false;
}
}
while(front!=rear)
{
int u=que[front++];
for(int v=1;v<=n;v++)
{
if(dist[v]>dist[u]+cost[u][v])
{
dist[v]=dist[u]+cost[u][v];
if(!vis[v])
{
vis[v]=true;
que[rear++]=v;
if(rear>=MAXN) rear=0;
}
}
}
vis[u]=false;
if(front>=MAXN)front=0;
}
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
scanf("%d",&cost[i][j]);
SPFA(1,n);
int ans=dist[n];
int loop1=dist[1];
SPFA(n,n);
int loopn=dist[n];
ans=min(ans,loop1+loopn);
printf("%d\n",ans);
}
return 0;
}