109 lines
2.6 KiB
C++
109 lines
2.6 KiB
C++
#include<iostream>
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using namespace std;
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#include<cstdio>
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#include<cstring>
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#define MAXN 1005
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#define INF 0x7f7f7f7f
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typedef __int64 type;
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struct node
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{
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int u, v;
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type w;
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}edge[MAXN * MAXN];
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int pre[MAXN], id[MAXN], vis[MAXN], n, m, pos;
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type in[MAXN];
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type Directed_MST(int root, int V, int E)
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{
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type ret = 0;
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while(true)
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{
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int i;
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for( i = 0; i < V; i++)
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in[i] = INF;
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for( i = 0; i < E; i++)
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{
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int u = edge[i].u;
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int v = edge[i].v;
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if(edge[i].w < in[v] && u != v)
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{
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pre[v] = u;
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in[v] = edge[i].w;
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if(u == root)
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pos = i;
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}
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}
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for( i = 0; i < V; i++)
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{
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if(i == root)
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continue;
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if(in[i] == INF)
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return -1;
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}
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int cnt = 0;
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memset(id, -1, sizeof(id));
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memset(vis, -1, sizeof(vis));
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in[root] = 0;
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for( i = 0; i < V; i++)
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{
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ret += in[i];
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int v = i;
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while(vis[v] != i && id[v] == -1 && v != root)
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{
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vis[v] = i;
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v = pre[v];
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}
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if(v != root && id[v] == -1)
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{
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for(int u = pre[v]; u != v; u = pre[u])
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id[u] = cnt;
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id[v] = cnt++;
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}
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}
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if(cnt == 0)
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break;
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for( i = 0; i < V; i++)
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if(id[i] == -1)
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id[i] = cnt++;
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for( i = 0; i < E; i++)
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{
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int u = edge[i].u;
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int v = edge[i].v;
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edge[i].u = id[u];
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edge[i].v = id[v];
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if(id[u] != id[v])
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edge[i].w -= in[v];
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}
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V = cnt;
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root = id[root];
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}
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return ret;
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}
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int main()
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{
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int i;
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while(scanf("%d%d", &n, &m) != EOF)
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{
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type sum = 0;
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for( i = 0; i < m; i++)
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{
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scanf("%d%d%I64d", &edge[i].u, &edge[i].v, &edge[i].w);
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edge[i].u++; edge[i].v++;
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sum += edge[i].w;
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}
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sum ++;
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for( i = m; i < m + n; i++)
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{
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edge[i].u = 0;
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edge[i].v = i - m + 1;
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edge[i].w = sum;
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}
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type ans = Directed_MST(0, n + 1, m + n);
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if(ans == -1 || ans - sum >= sum)
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puts("impossible");
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else
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printf("%I64d %d\n",ans - sum, pos - m);
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puts("");
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}
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return 0;
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}
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