The Unique MST----poj1679次小生成树

#include<stdio.h>
#include<string.h>
#include<map>
#include<iostream>
#include<algorithm>
#include<math.h>
#define N 110
#define INF 0xfffffff

using namespace std;

int Max

, used

, vis
, maps

, dist
, fa
, n;

void Init()
{
memset(vis, 0, sizeof(vis));
memset(used, 0, sizeof(used));
memset(Max, 0, sizeof(Max));
memset(fa, 0, sizeof(fa));
for(int i=0; i<=n; i++)
{
dist[i] = INF;
for(int j=0; j<=n; j++)
if(i == j)
maps[i][j] = 0;
else
maps[i][j] = INF;
}
}

int Prim(int start)
{
int ans=0;
for(int i=1; i<=n; i++)
{
dist[i] = maps[start][i];
fa[i] = start;
}
vis[start] = 1;
for(int i=1; i<=n; i++)
{
int Min = INF, index = -1;
for(int j=1; j<=n; j++)
{
if(vis[j]==0 && Min > dist[j])
{
Min = dist[j];
index = j;
}
}
if(index == -1)break;
vis[index] = 1;
ans += Min;
used[fa[index]][index] = used[index][fa[index]] = 1;
for(int j=1; j<=n; j++)
{
if(vis[j] == 1 && index != j)
{
Max[index][j] = Max[j][index] = max(Max[fa[index]][j], dist[index]);
}
else if(vis[j] == 0 && dist[j] > maps[index][j])
{
dist[j] = maps[index][j];
fa[j] = index;
}
}
}
return ans;
}

int SMST(int ans)
{
int Min = INF;
for(int i=1; i<=n;i++)
{
for(int j=i+1; j<=n; j++)
{
if(used[i][j]==0 && maps[i][j] != INF)
Min=min(Min, ans-Max[i][j]+maps[i][j]);
}
}
return Min;
}

int main()
{
int T, m, a, b, c;
scanf("%d", &T);
while(T--)
{
scanf("%d%d", &n, &m);
Init();
for(int i=0; i<m; i++)
{
scanf("%d%d%d", &a, &b, &c);
maps[a][b] = maps[b][a] = c;
}
int num1 = Prim(1);
int num2 = SMST(num1);
if(num1 != num2)
printf("%d\n", num1);
else
printf("Not Unique!\n");
}
return 0;
}