标签：res 工程 amp prim bool ret const 实现 scan
看卿学姐视频学到的题目
kruskal算法实现最小生成树
#include<bits/stdc++.h> using namespace std; const int maxn = 105; typedef long long ll; int n,m; struct edge{ int from ,to; ll cost; }E[maxn*maxn]; bool cmp(edge a,edge b) { return a.cost < b.cost; } int fa[maxn]; void init() { for(int i=1; i <= maxn; i++) fa[i] = i; } int fi(int x) { return fa[x] == x? x :fa[x] = fi(fa[x]); } void Union(int x,int y) { int f1=fi(x); int f2=fi(y); if(f1 != f2) fa[f1] = f2; } bool check(int x,int y) { return fi(x) == fi(y); } ll kruskal() { ll cnt = 0; sort(E+1,E+1+m,cmp); for(int i=1;i <= m;i++) { if(check(E[i].from,E[i].to)) continue; Union(E[i].from,E[i].to); cnt += E[i].cost; } return cnt; } int main () { while (~scanf("%d %d",&m,&n) && m){ init(); for(int i=1;i <= m;i++) { scanf("%d %d %lld",&E[i].from,&E[i].to,&E[i].cost); } ll res = kruskal(); for(int i=1; i <=n;i++) if(!check(i,1)) res = -1; if(res == -1) puts("?"); else printf("%lld\n",res); } return 0; }
prim 算法实现 （坑点好多 还要多写写 熟练一些
#include <bits/stdc++.h> using namespace std; typedef long long ll; const int maxn = 105; int n,m; struct edge{ int to; ll cost; edge(){} edge(int tt,ll cc):to(tt),cost(cc){} bool operator < (const edge &l)const{ return l.cost < cost; } }; priority_queue<edge> que; vector <edge> G[maxn]; bool vis[maxn]; void init() { memset(vis,0,sizeof(vis)); while (que.size()) que.pop(); for(int i=0;i <= n;i++) G[i].clear(); } ll prim() { vis[1] = 1;//要把1先加进去 ll cnt = 0; for(int i=0; i < G[1].size();i++)//从第一个顶点取出最短的边 que.push( G[1][i] ); while(que.size()) { edge e = que.top(); que.pop(); if(vis[e.to]) continue; vis[e.to] = 1; cnt += e.cost; for(int i=0;i< G[e.to].size();i++) que.push(G[e.to][i]); //cout << cnt<<endl; } return cnt; } int main () { while (~scanf("%d %d",&m,&n) && m){ init(); for(int i=1;i <= m;i++) { int u,v; ll cost; scanf("%d %d %lld",&u,&v,&cost); G[u].push_back(edge(v,cost)); G[v].push_back(edge(u,cost)); } ll res = prim(); for(int i=1; i <= n;i++) if( vis[i] == 0) res = -1; // for(int i=1; i <= n;i++) // printf("%d",vis[i]); if(res == -1) puts("?"); else printf("%lld\n",res); } return 0; }
标签：res 工程 amp prim bool ret const 实现 scan
原文地址：http://www.cnblogs.com/Draymonder/p/7302136.html
