hdu 3790 最小费用最短路
求最小费用最短路：即在路径长度尽量小的情况下使得花费尽量小。
其实就是在松弛多了一种情况就是：路径长度相等但费用小。
1 #include <algorithm> 2 #include <iostream> 3 #include <cstring> 4 #include <cstdio> 5 using namespace std; 6 7 const int INF = 99999999; 8 const int N = 1001; 9 const int M = 200000; 10 int head[N]; 11 int dist[N]; 12 int cost[N]; 13 bool visit[N]; 14 int n, m, e; 15 16 struct Edge 17 { 18 int v, next, w, c; 19 } edge[M]; 20 21 void addEdge( int u, int v, int w, int c ) 22 { 23 edge[e].v = v; 24 edge[e].w = w; 25 edge[e].c = c; 26 edge[e].next = head[u]; 27 head[u] = e++; 28 } 29 30 void dij( int s ) 31 { 32 memset( visit, false, sizeof(visit) ); 33 for ( int i = 0; i <= n; i++ ) 34 { 35 dist[i] = INF; 36 cost[i] = INF; 37 } 38 dist[s] = 0; 39 cost[s] = 0; 40 for ( int i = 1; i <= n; i++ ) 41 { 42 int u = 0; 43 for ( int j = 1; j <= n; j++ ) 44 { 45 if ( !visit[j] && dist[j] < dist[u] ) 46 { 47 u = j; 48 } 49 } 50 visit[u] = true; 51 for ( int j = head[u]; j != -1; j = edge[j].next ) 52 { 53 int v = edge[j].v, w = edge[j].w, c = edge[j].c; 54 if ( visit[v] ) continue; 55 if ( dist[u] + w < dist[v] ) 56 { 57 dist[v] = dist[u] + w; 58 cost[v] = cost[u] + c; 59 } 60 else if ( dist[u] + w == dist[v] && cost[u] + c < cost[v] ) 61 { 62 cost[v] = cost[u] + c; 63 } 64 } 65 } 66 } 67 68 int main () 69 { 70 while ( scanf("%d%d", &n, &m) != EOF ) 71 { 72 if ( n == 0 && m == 0 ) break; 73 e = 0; 74 memset( head, -1, sizeof(head) ); 75 while ( m-- ) 76 { 77 int u, v, w, c; 78 scanf("%d%d%d%d", &u, &v, &w, &c); 79 addEdge( u, v, w, c ); 80 addEdge( v, u, w, c ); 81 } 82 int s, t; 83 scanf("%d%d", &s, &t); 84 dij(s); 85 printf("%d %d\n", dist[t], cost[t]); 86 } 87 return 0; 88 }
