标签：最短路
8 7 0 1 1 2 2 3 3 4 4 5 5 6 6 7 8 8 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 0
Yes Yes
/*dijkstra*/
#include<cstdio>
#include<cstring>
#include<algorithm>
#define MAX 0x3f3f3f
using namespace std;
int map[111][111],dis[111],vis[111];
int n,m;
int min(int x,int y)
{
if(x >= y)
return y;
return x;
}
void dijkstra(int s)
{
int i,j,k;
memset(vis, 0, sizeof(vis));
for(i = 0; i < n; i++)
dis[i] = map[s][i];
vis[s]=1;
while(1)
{
k = -1;
for( i = 0; i < n; i++)
if(!vis[i]&&(k==-1||dis[i] < dis[k]))
k = i;
if(k == -1) break;
vis[k] = 1;
for(i = 0; i < n; i++)
dis[i] = min(dis[i],dis[k]+map[k][i]);
}
}
int main()
{
int i, j, k;
while(scanf("%d%d",&n,&m)!=EOF)
{
for(i = 0;i < n; i++)
for(j = 0;j < n; j++)
{
if(i == j)
map[i][j] = 0;
else
map[i][j] = MAX;
}
int a,b;
while(m--)
{
scanf("%d%d",&a,&b);
if(a!=b)
map[a][b] = map[b][a] = 1;
}
int flag = 1;
for(i = 0; i < n; i++)
{
dijkstra(i);
for( j = 0; j < n;j++)
{
if(dis[j]>7)
{
flag = 0;
break;
}
}
if(flag == 0)
break;
}
if(flag)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}
/*spfa*/
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<queue>
#include<algorithm>
using namespace std;
int dis[1111],vis[1111],head[2000],edgenum;
int n,m,flag;
struct node{
int start,end,len,next;
}p[20000];
void add(int u,int v, int w)
{
node E = {u,v,w,head[u]};
p[edgenum] = E;
head[u] = edgenum++;
}
void spfa(int s,int e)
{
memset(vis,0,sizeof(vis));
memset(dis,0x3f,sizeof(dis));
queue<int> q;
q.push(s);
dis[s] = 0;
vis[s] = 1;
while( !q.empty() )
{
int u = q.front(); q.pop(); vis[u] = 0;
for(int i=head[u]; i != -1; i=p[i].next)
{
int v = p[i].end;
if(dis[v] > dis[u]+p[i].len)
{
dis[v] = dis[u]+p[i].len;
if(!vis[v])
{
vis[v] = 1;
q.push(v);
}
}
}
}
if(dis[e] > 7)
{
flag = 1;return;
}
}
int main()
{
int i,j,k;
while(scanf("%d%d",&n,&m)!=EOF)
{
memset(head,-1,sizeof(head));
edgenum = 0;
int a,b;
while(m--)
{
scanf("%d%d",&a,&b);
add(a,b,1);
add(b,a,1);
}
flag = 0;
for(i = 0; i<n; i++)
{
for(j = i +1; j < n; j++)
{
spfa(i,j);
if(flag) break;
}
}
if(flag)
printf("No\n");
else
printf("Yes\n");
}
return 0;
}
/* floyd */
#include<stdio.h>
#include<string.h>
#define min(a,b) a>b?b:a
#define INF 0x3f3f3f3f
int n,m;
int dis[111][111];
void floyd()
{
int i,j,k;
for(k = 0; k < n; k++)
for(i = 0; i < n; i++)
for(j = 0; j < n; j++)
dis[i][j] = min( dis[i][j], dis[i][k]+dis[k][j] );
}
int main()
{
int i,j,k,a,b;
while(scanf("%d%d",&n,&m)!=EOF)
{
memset(dis,0x3f,sizeof(dis));
while(m--)
{
scanf("%d%d",&a,&b);
dis[a][b] = dis[b][a] = 1;
}
floyd();
int flag = 0;
for(i = 0; i < n;i++)
for(j = 0; j < n;j++)
{
if( flag ) break;
if(dis[i][j] > 7)
{
flag = 1;break;
}
}
if(flag) printf("No\n");
else
printf("Yes\n");
}
return 0;
}
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标签：最短路
原文地址：http://blog.csdn.net/liu6886/article/details/47839067
