# "Chu-Liu Algorithm" "Minimum tree diagram" hdu6141 I am your father!

Source: Internet
Author: User

Test instructions: give you a picture with the right direction, let you ask for the maximum tree shape chart. And on this premise ordered N-junction father's number is the smallest.

The game was a two-point, tle.

The weight of each side can actually be multiplied by 1000, for the parent edge of the n node, plus the weight of the (999-parent node number) size, so that the maximum tree is guaranteed, the number of the father of the N node is the smallest.

Online to find a Zhu-Liu algorithm of the board , the edge of the right to take negative can run the largest tree diagram.

`#include <cstdio> #include <string> #include <cstring> #define MAXN 1005 #define MAXM 10005 using n  Amespace std;      struct node {int u, v;  int W;  }EDGE[MAXM];  int PRE[MAXN], ID[MAXN], VIS[MAXN], N, m;  int IN[MAXN];      typedef int type; #define INF 2000000000type directed_mst (int root, int V, int E) {type ret = 0;          while (true) {//1.?????          for (int i = 0; i < V; i++) in[i] = INF;              for (int i = 0; i < E; i++) {int u = edge[i].u;              int v = EDGE[I].V;          if (EDGE[I].W < in[v] && u! = V) {Pre[v] = u; in[v] = EDGE[I].W;}              } for (int i = 0; i < V; i++) {if (i = = root) continue;          if (in[i] = = INF) return-1;//???????????,???????          }//2.??          int cnt = 0;          memset (ID,-1, sizeof (ID));          memset (Vis,-1, sizeof (VIS));          In[root] = 0; for (int i = 0; i < V; i++)//?????              {ret + = In[i];              int v = i;              while (vis[v]! = i && id[v] = = 1 && v! = root)//?????????,?????????,???????                  {Vis[v] = i;              v = pre[v];              } if (v! = root && id[v] = =-1)//??                  {for (int u = pre[v]; u = v; u = pre[u]) id[u] = cnt;              ID[V] = cnt++; }} if (cnt = = 0) break;   //??                break for (int i = 0; i < V; i++) if (id[i] = = 1) id[i] = cnt++;          3.????              for (int i = 0; i < E; i++) {int u = edge[i].u;              int v = EDGE[I].V;              EDGE[I].U = Id[u];              EDGE[I].V = Id[v];          if (id[u]! = Id[v]) EDGE[I].W-= In[v];          } V = cnt;      root = Id[root];  } return ret; } int Zu,xs[10005],ys[10005],zs[10005];int Main () {//freopen ("1009.in", "R",stdin);//freopen ("1009.out", "w", stdout); scanf ("%d", &zu);        for (; zu;--zu) {scanf ("%d%d", &n, &m);              for (int i = 0; i < m; i++) {scanf ("%d%d%d", &edge[i].u, &AMP;EDGE[I].V, &AMP;EDGE[I].W);              edge[i].u--;              edge[i].v--;            edge[i].w*=1000;            if (edge[i].v==n-1) {edge[i].w+= (999-EDGE[I].U);            } EDGE[I].W=-EDGE[I].W;            xs[i]=edge[i].u;            YS[I]=EDGE[I].V;            ZS[I]=EDGE[I].W;             if (edge[i].u = = edge[i].v) {EDGE[I].W = INF;            Zs[i] = INF;          }} int ans = directed_mst (0, N, m);    printf ("%d%d\n", (-ans)/1000,1000-(-ans)%1000);  } return 0;   }`

"Chu-Liu Algorithm" "Minimum tree diagram" hdu6141 I am your father!

Related Keywords:

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

## A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

• #### Sales Support

1 on 1 presale consultation

• #### After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

• Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.