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提供一种思路:可以吧1点的值设为无穷,然后其他点赋值为0,应该很多算法都可以跑我跑的是spfa
#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#include<math.h>
#include<set>
#include<stack>
#include<vector>
#include<map>
#include<queue>
#define myself i,l,r
#define lson i<<1
#define rson i<<1|1
#define Lson i<<1,l,mid
#define Rson i<<1|1,mid+1,r
#define half (l+r)/2
#define inff 0x3f3f3f3f
#define lowbit(x) x&(-x)
#define PI 3.14159265358979323846
#define min4(a,b,c,d) min(min(a,b),min(c,d))
#define min3(x,y,z) min(min(x,y),min(y,z))
#define pii make_pair
#define pr pair<int,int>
const int dir[4][2]={0,1,0,-1,1,0,-1,0};
typedef long long ll;
const ll inFF=9223372036854775807;
typedef unsigned long long ull;
using namespace std;
const int maxn=1e5+5;
int head[maxn],sign;
int d[maxn],vis[maxn];
int n,m;
struct node
{
int to,p,val;
}edge[maxn];
void add(int u,int v,int val)
{
edge[sign]=node{v,head[u],val};
head[u]=sign++;
}
void init()
{
sign=0;
memset(head,-1,sizeof(head));
}
int spfa()
{
for(int i=0;i<=n;i++)
{
d[i]=0;
vis[i]=0;
}
d[1]=inff;
queue<int> q;
q.push(1);
while(!q.empty())
{
int u=q.front();
q.pop(),vis[u]=0;
for(int i=head[u];~i;i=edge[i].p)
{
int v=edge[i].to;
if(d[v]<min(edge[i].val,d[u]))
{
d[v]=min(edge[i].val,d[u]);
if(!vis[v])
{
q.push(v);
vis[v]=1;
}
}
}
}
return d[n];
}
int main()
{
int t,x,y,z,p=0;
cin>>t;
while(t--)
{
scanf("%d %d",&n,&m);
init();
for(int i=1;i<=m;i++)
{
scanf("%d %d %d",&x,&y,&z);
add(x,y,z),add(y,x,z);
}
printf("Scenario #%d:\n",++p);
cout<<spfa()<<endl;
printf("\n");
}
return 0;
}
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