Prim 求 MST| INIT: cost[][]耗费矩阵(inf为无穷大)；

| Prim 求 MST

| INIT: cost[][] 耗费矩阵 (inf 为无穷大 );

| CALL: prim(cost, n); 返回 -1 代表原图不连通 ;

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#define typec int // type of cost

const typec inf = 0x3f3f3f3f; // max of cost

int vis[V]; typec lowc[V];

typec prim(typec cost[][V], int n) // vertex: 0 ~ n-1

{

int i, j, p;

typec minc, res = 0;

memset(vis, 0, sizeof (vis));

vis[0] = 1;

for (i=1; i<n; i++) lowc[i] = cost[0][i];

for (i=1; i<n; i++) {

minc = inf; p = -1;

for (j=0; j<n; j++)

if (0 == vis[j] && minc > lowc[j]) {

minc = lowc[j]; p = j;

}

if (inf == minc) return -1; // 原图不连通

res += minc; vis[p] = 1;

for (j=0; j<n; j++)

if (0 == vis[j] && lowc[j] > cost[p][j])

lowc[j] = cost[p][j];

}

return res;

}