Dijkstra+二叉堆优化
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <math.h> 4 #include <string.h> 5 #define MAXC 501 6 #define MAXN 801 7 #define MAXM 1451 * 2 8 #define INF 0x7FFFFFFF 9 using namespace std; 10 struct edge 11 { 12 edge *next; 13 int t, v; 14 } ES[MAXM]; 15 struct HeapElement 16 { 17 int key, value; 18 }; 19 struct MinHeap 20 { 21 HeapElement H[MAXN]; 22 int size; 23 int Position[MAXN]; 24 void init() 25 { 26 H[size = 0].value = -INF; 27 } 28 void ins(int key, int value) 29 { 30 int f; 31 HeapElement p = {key, value}; 32 for (int i = ++size; p.value < H[f = i >> 1].value; i=f) 33 { 34 H[i] = H[f]; 35 Position[H[i].key] = i; 36 } 37 H[i] = p; 38 Position[H[i].key] = i; 39 } 40 void decrease(int key, int value) 41 { 42 int f; 43 HeapElement p = {key, value}; 44 for (int i = Position[key]; p.value < H[f = i >> 1].value; i=f) 45 { 46 H[i] = H[f]; 47 Position[H[i].key] = i; 48 } 49 H[i] = p; 50 Position[H[i].key] = i; 51 } 52 void delmin() 53 { 54 int c; 55 HeapElement p = H[size--]; 56 for (int i = 1; (c = i << 1) <= size; i=c) 57 { 58 if (c + 1 <= size && H[c + 1].value < H[c].value) 59 ++c; 60 if (H[c].value < p.value) 61 { 62 H[i] = H[c]; 63 Position[H[i].key] = i; 64 } 65 else 66 break; 67 } 68 H[i] = p; 69 Position[H[i].key] = i; 70 } 71 } H; 72 int N, M, C, EC = -1, Ans = INF; 73 int Cow[MAXC], sp[MAXN]; 74 edge *V[MAXN]; 75 inline void addedge(int a, int b, int c) 76 { 77 ES[++EC].next = V[a]; 78 ES[EC].t = b; 79 ES[EC].v = c; 80 V[a] = &ES[EC]; 81 } 82 void init() 83 { 84 int a, b, c; 85 scanf("%d %d %d", &C, &N, &M); 86 for (int i = 1; i <= C; ++i) 87 scanf("%d", &Cow[i]); 88 for (int i = 1; i <= M; ++i) 89 { 90 scanf("%d %d %d", &a, &b, &c); 91 addedge(a, b, c); 92 addedge(b, a, c); 93 } 94 } 95 void Dijkstra(int S) 96 { 97 sp[S] = 0; 98 H.decrease(S, 0); 99 for (int i = S, j; ; ) 100 { 101 H.delmin(); 102 for (edge *k = V[i]; k; k = k -> next) 103 { 104 if (sp[i] + k -> v < sp[j = k -> t]) 105 { 106 sp[j] = sp[i] + k -> v; 107 H.decrease(j, sp[j]); 108 } 109 } 110 if (H.size) 111 i = H.H[1].key; 112 else 113 break; 114 } 115 } 116 void solve() 117 { 118 int Total; 119 for (int i = 1, j; i <= N; ++i) 120 { 121 H.init(); 122 for (j = 1; j <= N; ++j) 123 { 124 H.ins(j, INF); 125 sp[j] = INF; 126 } 127 Total = 0; 128 Dijkstra(i); 129 for (j = 1; j <= C; ++j) 130 Total += sp[Cow[j]]; 131 if (Total < Ans) 132 Ans = Total; 133 } 134 } 135 int main() 136 { 137 init(); 138 solve(); 139 printf("%d\n", Ans); 140 return 0; 141 }
posted on 2013-06-12 10:38 初昱天殷HatsuakiraTenan 阅读(236) 评论(0) 编辑 收藏 举报