Prim 普裡姆演算法的java實現__演算法

  普裡姆演算法，主要是用於求最小產生樹的典型演算法，其實現簡單。

  package algorithm; import java.util.Scanner; public class Prim { public static void main(String[] args) { Scanner sc = new Scanner(System.in); while (sc.hasNext()) { int n = sc.nextInt(); int m = sc.nextInt(); if (n == 0 && m == 0) break; int[][] map = new int[n][n]; for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) { map[i][j] = Integer.MAX_VALUE; } } for (int i = 0; i < m; ++i) { int u = sc.nextInt(); int v = sc.nextInt(); int w = sc.nextInt(); map[u][v] = w; map[v][u] = w; } Edge[] e = new Edge[n]; prime(map, e, n); for (int i = 0; i < n - 1; ++i) { System.out.println(e[i].from + " " + e[i].end + " " + e[i].weight); } } } static void prime(int[][] map, Edge[] e, int n) { for (int i = 0; i < n - 1; ++i) { e[i] = new Edge(); e[i].from = 0; e[i].end = i + 1; e[i].weight = map[0][i + 1]; } for (int k = 1; k < n; ++k) { int m = -1; int min = Integer.MAX_VALUE; for (int j = k - 1; j < n - 1; ++j) { if (e[j].weight < min) { min = e[j].weight; m = j; } } Edge tmp = e[m]; e[m] = e[k - 1]; e[k - 1] = tmp; int c = k - 1; for (int j = k; j < n - 1; ++j) { int t = e[j].end; int w = e[j].weight; if (map[e[c].end][t] < w) { e[j].from = e[c].end; e[j].weight = map[e[c].end][t]; } } } } private static class Edge { int from; int end; int weight; } }