Dijkstra最短路算法和最小生成树算法
目录
Dijkstra最短路算法和最小生成树算法
Dijkstra最短路：
### **Dijkstra最短路：**
#include <bits/stdc++.h>
using namespace std;
const int N = 510;
int n, m,map[N][N],dist[N];
bool st[N];
int dijkstra()
{
int i,j,t;
memset(dist, 0x3f, sizeof dist);
dist[1] = 0;
for (i = 0; i < n - 1; i ++ )
{
t = -1;
for (j = 1; j <= n; j ++ )
if (!st[j] && (t == -1 || dist[t] > dist[j]))
t = j;
st[t] = true;
for (j = 1; j <= n; j ++ )
dist[j] = min(dist[j], dist[t] + map[t][j]);
}
if (dist[n]==0x3f3f3f3f) return -1;//有没有最短路
return dist[n];
}
int main()
{
scanf("%d%d", &n, &m);
memset(map, 0x3f, sizeof map);
while (m -- )
{
int x,y,z;
scanf("%d%d%d",&x,&y,&z);
map[x][y] = min(map[x][y],z);//处理重边
}
printf("%d\n", dijkstra());
return 0;
}最小生成树:
### 最小生成树:
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e3+7;
int minn[N];
int g[N][N];
int vis[N];
ll sum=0;
int n,m;
void pr(){
minn[1]=0;
for(int i=1;i<=n;i++){
int t=-1;
for(int j=1;j<=n;j++){
if(!vis[j]&&(t==-1||minn[t]>minn[j])){
t=j;
}
}
if(minn[t]==0x3f3f3f3f||t==-1){
cout<<"orz";
return ;
}
vis[t]=1;
sum+=minn[t];
for(int j=1;j<=n;j++){
if(!vis[j])minn[j]=min(minn[j],g[j][t]);
}
}
cout<<sum;
}
void solve(){
cin>>n>>m;
memset(g,0x3f,sizeof g);
memset(minn,0x3f,sizeof minn);
for(int i=1;i<=m;i++){
int a,b,c;
cin>>a>>b>>c;
g[a][b]=min(g[a][b],c);
g[b][a]=min(g[b][a],c);
}
pr();
}
int main(){
int T=1;
while(T--){
solve();
}
return 0;
}