【HDU1102】Constructing Roads（MST基础题）
最小生成树水题。prim一次AC
1 #include <iostream> 2 #include <cstring> 3 #include <cstdlib> 4 #include <cstdio> 5 #include <cctype> 6 #include <cmath> 7 #include <algorithm> 8 #include <numeric> 9 10 #define typec int 11 using namespace std; 12 13 const int V = 105; 14 const int inf = 0xffff; 15 int vis[V]; typec lowc[V]; 16 int Map[105][105]; 17 18 typec prim (typec cost[][V], int n) { 19 int i, j, p; 20 typec minc, res = 0; 21 memset(vis, 0, sizeof(vis)); 22 vis[0] = 1; 23 for (i = 1; i < n; ++ i) lowc[i] = cost[0][i]; 24 for (i = 1; i < n; ++ i) { 25 minc = inf; p = -1; 26 for (j = 0; j < n; ++ j) { 27 if (0 == vis[j] && minc > lowc[j]) { 28 minc = lowc[j]; p = j; 29 } 30 } 31 if (inf == minc) return -1; 32 res += minc; vis[p] = 1; 33 for (j = 0; j < n; ++ j) { 34 if (0 == vis[j] && lowc[j] > cost[p][j]) { 35 lowc[j] = cost[p][j]; 36 } 37 } 38 } 39 return res; 40 } 41 42 int main () { 43 //cout << inf <<endl; 44 int n; 45 while (cin >> n) { 46 for (int i = 0 ; i < n; ++ i) { 47 for (int j = 0 ; j < n; ++ j) { 48 scanf("%d", &Map[i][j]); 49 } 50 } 51 int ok_line; cin >> ok_line; 52 for (int i = 0; i < ok_line; ++ i) { 53 int s, e; 54 scanf("%d%d", &s, &e); 55 Map[s - 1][e - 1] = Map[e - 1][s - 1] = 0; 56 } 57 cout << prim(Map, n) << endl; 58 } 59 return 0; 60 }
