最小生成树-Prim算法

Prim算法是和Kruskal算法对应的一个避圈法，两者的百度百科都写得蛮好，不赘述

  代码

PASCAL代码

c代码

C++代码

Mathematica代码（如下）

Prim[tu_, dian_] := Module[(*中括号要紧跟Module*)
  {diancount = 1,(*点集*)
   visit = Table[False, {i, 1, dian}],(*标记是否访问过*)
   vall = tu[[1]],(*初始取值*)
   pre = Table[1, {i, 1, dian}],(*前节点*)
   st = 1, en = 1, val = Infinity,
   result = Table[Infinity, {i, 1, dian}, {j, 1, dian}],(*最终结果*)
   flag = True, i, j},
  visit[[1]] = True;
  While[diancount != dian,
   val = Infinity;
   Do[(*得到最小的那条边*)
    If[visit[[i]] == True, Continue[]];
    If[vall[[i]] < val, en = i; val = vall[[i]]]
    , {i, 1, dian}
    ];
   If[val == Infinity, flag = False; Break[]];(*如果所有的边都是无穷，说明图不连通*)
   st = pre[[en]];
   result[[st]][[en]] = val; result[[en]][[st]] = val;
   diancount++;
   visit[[en]] = True;
   Do[(*更新*)
    If[visit[[j]] == True, Continue[]];
    If[tu[[en]][[j]] < vall[[j]], vall[[j]] = tu[[en]][[j]]; 
     pre[[j]] = en]
    , {j, 1, dian}]
   ];
  If[flag, Return[result], Print["Something goes Wrong-", diancount]]
  ]

Input:
tuer={{INF, 7, INF, 5, INF, INF, INF}, {7, INF, 8, 9, 7, INF, INF}, {INF, 
  8, INF, INF, 5, INF, INF}, {5, 9, INF, INF, 15, 6, INF}, {INF, 7, 5,
   15, INF, 8, 9}, {INF, INF, INF, 6, 8, INF, 11}, {INF, INF, INF, 
  INF, 9, 11, INF}}
Prim[tuer, 7]

Output:
{{INF, 7, INF, 5, INF, INF, INF}, {7, INF, INF, INF, 7, INF, 
  INF}, {INF, INF, INF, INF, 5, INF, INF}, {5, INF, INF, INF, INF, 6, 
  INF}, {INF, 7, 5, INF, INF, INF, 9}, {INF, INF, INF, 6, INF, INF, 
  INF}, {INF, INF, INF, INF, 9, INF, INF}}