思路:Dijkstra求最短路径,将0节点作为原点,求出到各个点的距离。
#include <stdio.h> #include <string.h> #include <algorithm> using namespace std; #define inf 0x3fffffff #define N 1005 int T,S,D,n,map[N][N],vis[N],cast[N],s[N],e[N]; void Dijkstra() { int i,j,minn,pos; memset(vis,0,sizeof(vis)); vis[0] = 1; for(i = 0; i<=n; i++) cast[i] = map[0][i]; for(i = 1; i<=n; i++) { minn = inf; for(j = 1; j<=n; j++) { if(cast[j]<minn && !vis[j]) { pos = j; minn = cast[j]; } } vis[pos] = 1; for(j = 1; j<=n; j++) { if(cast[pos]+map[pos][j]<cast[j] && !vis[j]) cast[j] = cast[pos]+map[pos][j]; } } } int main() { int x,y,z; while(~scanf("%d%d%d",&T,&S,&D)) { n = 0; for(int i = 0; i<N; i++) { for(int j = 0; j<N; j++) map[i][j] = inf; map[i][i] = 0; } while(T--) { scanf("%d%d%d",&x,&y,&z); n = max(max(n,x),y);//n标记节点个数 if(z<map[x][y]) map[x][y] = map[y][x] = z; } for(int i = 0; i<S; i++) { scanf("%d",&s[i]); map[0][s[i]] = map[s[i]][0] = 0; } for(int i = 0; i<D; i++) scanf("%d",&e[i]); Dijkstra(); int minn = inf; for(int i = 0; i<D; i++) minn = min(minn,cast[e[i]]); printf("%d\n",minn); } return 0; }