最小生成树的prim算法（java）

/** * 最小生成树的prim算法 * @author liuy */public class Prim {public static void prim(int num, float[][] weight) { //num为顶点数，weight为权float[] lowcost = new float[num + 1]; //到新集合的最小权int[] closest = new int[num + 1]; //代表与s集合相连的最小权边的点boolean[] s = new boolean[num + 1]; //s[i] == true代表i点在s集合中s[1] = true; //将第一个点放入s集合for(int i = 2; i <= num; i++) { //初始化辅助数组lowcost[i] = weight[1][i];closest[i] = 1;s[i] = false;}for(int i = 1; i < num; i++) {float min = Float.MAX_VALUE;int j = 1;for(int k = 2; k <= num; k++) {if((lowcost[k] < min) && (!s[k])) {//根据最小权加入新点min = lowcost[k];j = k;}}System.out.println("加入点" + j + ". " + j + "---" + closest[j]);//新加入点的j和与j相连的点s[j] = true;//加入新点jfor(int k = 2; k <= num; k++) {if((weight[j][k] < lowcost[k]) && !s[k]) {//根据新加入的点j,求得最小权lowcost[k] = weight[j][k];closest[k] = j;}}}}public static void main(String[] args) {// ①// / | /// 6 1 5// / | /// ②-5--③--5--④// / // /// 3 6 4 2// // //// ⑤--6-⑥//最小生成树为：// ①// | // 1 // | // ②-5--③④// / / /// 3 4 2// / //// ⑤⑥//float m = Float.MAX_VALUE;float[][] weight = {{0, 0, 0, 0, 0, 0, 0},{0, m, 6, 1, 5, m, m},{0, 6, m, 5, m, 3, m},{0, 1, 5, m, 5, 6, 4},{0, 5, m, 5, m, m, 2},{0, m, 3, 6, m, m, 6},{0, m, m, 4, 2, 6, m}};//上图的矩阵prim(weight.length - 1, weight);//加入点3. 3---1//加入点6. 6---3//加入点4. 4---6//加入点2. 2---3//加入点5. 5---2}}