1 #include <cstdio>2 #include <cstring>3 4 #define INF 21474836475 #define N 10000016 7 long long n,m,f,nxt[N],fst[N],v[N],e[N],cnt = 0,dis[N],queue[N];8 9 int t,w;bool inqueue[N] = {0};  //Dijkstra10 11 bool book[1000001] = {0};        //spfa12 13 void Add(int a,int b,int c){14     cnt++;15     if(a == f)dis[b] = c;16     e[cnt] = b;17     nxt[cnt] = fst[a];18     fst[a] = cnt;19     v[cnt] = c;20 }21 int main()22 {23     memset(fst,-1,sizeof(fst));24     memset(nxt,-1,sizeof(nxt));25     scanf("%lld %lld %lld",&n,&m,&f);26     for(int i = 0;i <= n + 10;i++)27         dis[i] = INF;28     for(int i = 1;i <= m;i++){29         long long a,b,c;30         scanf("%lld %lld %lld",&a,&b,&c);31         Add(a,b,c);32     }33     34     int choose = 2;35     36     if(choose == 1){37         //Dijkstra38         dis[f] = 0;39         book[f] = 0;40         for(int i = 1;i <= n;i++){41             int Mn = INF,x;42             for(int j = 1;j <= n;j++)43                 if(dis[j] < Mn && !book[j])44                     Mn = dis[j],x = j;45             book[x] = 1;46             for(int k = fst[x];k != -1;k = nxt[k])47                 if(v[k] + dis[x] < dis[e[k]])48                     dis[e[k]] = v[k] + dis[x]; 49         }50     }51     if(choose == 2){52         //spfa53         memset(inqueue,0,sizeof(inqueue));54         t = w = 1;55         queue[1] = f;56         inqueue[f] = 1;57         dis[f] = 0;58         while(t <= w){ 59             inqueue[queue[t]] = 0;60             for(int j = fst[queue[t]];j != -1;j = nxt[j]){61                 if(dis[queue[t]] + v[j] <= dis[e[j]]/*一定为"<="*/){62                     dis[e[j]] = dis[queue[t]] + v[j];63                     if(!inqueue[e[j]]){64                         w++;65                         queue[w] = e[j];66                         inqueue[e[j]] = 1;67                     }68                 }            69             }70             t++;71         }72     }73     74     for(int i = 1;i <= n;i++){75         //printf("%lld %c %lld : %lld\n",f,26,i,dis[i]);76         printf("%d ",dis[i]);77     }78         79     return 0;80 }81 /*82 ---data---83 84 4 5 185 1 4 986 2 4 687 1 2 588 4 3 889 1 3 790 ans:91 0 5 7 992 93 4 6 194 1 2 295 2 3 296 2 4 197 1 3 598 3 4 399 1 4 4
100 ans:
101 0 2 4 3
102
103 6 9 1
104 1 2 1
105 1 3 12
106 2 3 9
107 2 4 3
108 3 5 5
109 4 3 4
110 4 5 13
111 4 6 15
112 5 6 4
113 ans:
114 0 1 8 4 13 17
115 */