hdu 5294 Tricks Device
中规中矩的做法,第二发SAP。贴一发留恋。
#include<cstdio> #include<cstring> #include<algorithm> #include<queue> #include<vector> using namespace std; const int INF=0x3f3f3f3f; const int maxn=2008; struct fuck{ int v,w; bool operator<(const fuck &a) const { return w>a.w; } }; struct shit{ int u,v,cap,flow,next; }edge[maxn<<6]; vector<fuck> g[maxn]; vector<int> distree[maxn]; int dis[maxn],bitch[maxn],head[maxn]; bool vis[maxn]; int tol=0,len; void init() { tol=0; len=1; memset(head,-1,sizeof(head)); } void addedge(int u,int v,int w) { edge[tol].u=u; edge[tol].v=v; edge[tol].cap=w; edge[tol].flow=0; edge[tol].next=head[u]; head[u]=tol++; edge[tol].u=v; edge[tol].v=u; edge[tol].cap=0; edge[tol].flow=0; edge[tol].next=head[v]; head[v]=tol++; } void dfs(int u) { int v; for(int i=0;i<distree[u].size();i++) { v=distree[u][i]; addedge(u,v,1); if(vis[v]) continue; vis[v]=true; len++; dfs(v); } } void dij(int n) { priority_queue<fuck> q; int u,v,i,w; fuck pp; memset(dis,INF,sizeof(dis)); memset(vis,false,sizeof(vis)); pp.v=1;pp.w=0;bitch[1]=0;dis[1]=0; q.push(pp); while(!q.empty()) { pp=q.top();q.pop(); u=pp.v; if(vis[u]) continue; vis[u]=true; for(i=0;i<g[u].size();i++) { v=g[u][i].v;w=g[u][i].w; if(dis[v]>=dis[u]+w) { if(dis[v]==dis[u]+w) { if(bitch[v]>bitch[u]+1) bitch[v]=bitch[u]+1; distree[v].push_back(u); } else { dis[v]=dis[u]+w; bitch[v]=bitch[u]+1; pp.w=dis[v];pp.v=v; q.push(pp); distree[v].clear(); distree[v].push_back(u); } } } } } int dep[maxn],gap[maxn]; void bfs(int start,int last) { memset(dep,-1,sizeof(dep)); memset(gap,0,sizeof(gap)); queue<int> q; q.push(last);dep[last]=0;gap[0]=1; int i,u,v; while(!q.empty()) { u=q.front();q.pop(); for(i=head[u];i!=-1;i=edge[i].next) { v=edge[i].v; if(edge[i].cap!=edge[i].flow||dep[v]!=-1) continue; q.push(v); dep[v]=dep[u]+1; ++gap[dep[v]]; } } } int sap(int start,int last) { int max_flow=0,i,u,v,w; bfs(start,last); int cur[maxn]; int S[maxn]; int top=0; for(i=last;i<=start;i++) cur[i]=head[i]; u=start; while(dep[start]<=len) { if(u==last) { int temp=INF; int inser; for(i=0;i<top;i++) if(temp>edge[S[i]].cap-edge[S[i]].flow) { temp=edge[S[i]].cap-edge[S[i]].flow; inser=i; } for(i=0;i<top;i++) { edge[S[i]].flow+=temp; edge[S[i]^1].flow-=temp; } max_flow+=temp; top=inser; u=edge[S[top]].u; } if(u!=last&&gap[dep[u]-1]==0) break; for(i=cur[u];i!=-1;i=edge[i].next) if(edge[i].cap>edge[i].flow&&dep[u]==dep[edge[i].v]+1) break; if(i!=-1) { cur[u]=i; S[top++]=i; u=edge[i].v; } else { int mi=len+1; for(i=head[u];i!=-1;i=edge[i].next) { if(edge[i].cap==edge[i].flow) continue; if(mi>dep[edge[i].v]) { mi=dep[edge[i].v]; cur[u]=i; } } --gap[dep[u]]; dep[u]=mi+1; ++gap[dep[u]]; if(u!=start) u=edge[S[--top]].u; } } return max_flow; } int main() { int i,j,n,m,u,v,w; fuck pp; //freopen("1007.in","r",stdin); //freopen("fuck.txt","w",stdout); while(scanf("%d%d",&n,&m)==2) { for(i=0;i<=n;i++) { g[i].clear(); distree[i].clear(); } init(); for(i=0;i<m;i++) { scanf("%d%d%d",&u,&v,&w); pp.v=v;pp.w=w; g[u].push_back(pp); pp.v=u; g[v].push_back(pp); } dij(n); memset(vis,false,sizeof(vis)); vis[n]=true; dfs(n); int y=sap(n,1); printf("%d %d\n",y,m-bitch[n]); } return 0; }