次小生成树

The Unique MST POJ - 1679

const int LEN = 100000;//有多少条边const int LEN2 = 110;//有多少个点int N,M;struct Node{    int x;    int y;    int weight;};Node node[LEN];bool operator <(const Node &a,const Node &b){    return a.weight < b.weight;}bool cmp(const Node &a,const Node &b){    return a.weight  < b.weight;}int sign1[LEN];int Max_edge[LEN2][LEN2];//最小生成树从i到j最权值最大边的权值int Matrix[LEN2][LEN2];bool  sign[LEN2][LEN2];int F[LEN2];int vis[LEN2];void Init(void){    me(sign1);    for(int i = 0; i <= N; ++i)        F[i] = i;    me(sign);    me(vis);}int Find(int x){    return x == F[x]?x:F[x] = Find(F[x]);}void Dfs(int x){    for(int i =1; i <= N; ++i)    {        if(sign[x][i]&&!vis[i])        {            Max_edge[x][i] = Max_edge[i][x] = Matrix[x][i];            for(int j = 1; j <= N; ++j)            {                if(vis[j]&&j!=x)                {                    Max_edge[i][j] = Max_edge[j][i] = max(Max_edge[j][x],Max_edge[x][i]);                }            }            vis[i] = 1;            Dfs(i);        }    }}int main(){    int T;    cin>>T;    while(T--)    {        cin>>N>>M;        if(M>0)        {            Init();            for(int i = 0; i < M; ++i)            {                scanf("%d %d %d",&node[i].x,&node[i].y,&node[i].weight);                Matrix[node[i].x][node[i].y] = Matrix[node[i].y][node[i].x] = node[i].weight;            }            sort(node,node+M);            int All_cost = 0;            for(int i = 0; i < M; ++i)            {                int x = Find(node[i].x);                int y = Find(node[i].y);                if(x!=y)                {                    sign[node[i].x][node[i].y] = sign[node[i].y][node[i].x] = 1;                    F[x] = y;                    sign1[i] = 1;                    All_cost += node[i].weight;                }            }            vis[1] = 1;            Dfs(1);            int flag = 0;            for(int i = 0; i < M; ++i)            {                if(!sign1[i]&&node[i].x!=node[i].y)                {                    if(Max_edge[node[i].x][node[i].y] >= node[i].weight)                    {                        flag = 1;                        break;                    }                }            }            if(flag)                printf("Not Unique!\n");            else                printf("%d\n",All_cost);        }        else            cout<<0<<endl;    }    return 0;}