mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
121 lines
2.8 KiB
C++
121 lines
2.8 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<algorithm>
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#define N 110
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#define M 10100
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#define inf 10000000
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using namespace std;
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int n,k,dis[N],head[N],gap[N],f[N];
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int a[M*2];
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struct Edge{
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int v,c,next;
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}edge[M*2];
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void init(){
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memset(head,-1,sizeof(head));
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memset(dis,0,sizeof(dis));
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memset(gap,0,sizeof(gap));
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memset(f,0,sizeof(f));
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k=0;
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}
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void addedge(int u,int v,int c){
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edge[k].v=v;
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edge[k].c=c;
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edge[k].next=head[u];
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head[u]=k++;
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edge[k].v=u;
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edge[k].c=0;
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edge[k].next=head[v];
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head[v]=k++;
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}
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int dfs(int p,int s,int t,int limit){
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if(p==t)return limit;
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for(int i=head[p];i!=-1;i=edge[i].next){
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int v=edge[i].v;
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if(dis[p]==(dis[v]+1) && edge[i].c>0){
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int c=dfs(v,s,t,min(limit,edge[i].c));
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if(c<0)return c;
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if(c>0){
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edge[i].c-=c;
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edge[i^1].c+=c;
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return c;
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}
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}
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}
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int tmp=n;
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for(int i=head[p];i!=-1;i=edge[i].next){
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int v=edge[i].v;
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if(edge[i].c>0)
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tmp=min(tmp,dis[v]+1);
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}
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if(--gap[dis[p]]==0 || dis[s]>=n)return -1;
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++gap[dis[p]=tmp];
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return 0;
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}
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int SAP(int s,int t){
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gap[s]=n;
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int cap=0,now=0;
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while(~(now=dfs(s,s,t,inf))) cap+=now;
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return cap;
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}
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void dfs1(int u){
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f[u]=1;
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for(int i=head[u];i!=-1;i=edge[i].next){
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int v=edge[i].v;
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if(f[v]==0 && edge[i].c>0)
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dfs1(v);
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}
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}
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void dfs2(int u){
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f[u]=2;
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for(int i=head[u];i!=-1;i=edge[i].next){
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int v=edge[i].v;
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if(f[v]==0 && edge[i^1].c>0)
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dfs2(v);
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}
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}
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int main(){
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int t,T,i,j;
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int V,E;
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int u,v,c;
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int sap,ans;
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int a1,a2;
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scanf("%d",&T);
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for(t=1;t<=T;t++){
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init();
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scanf("%d %d",&V,&E);
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for(i=1;i<=E;i++){
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scanf("%d %d %d",&u,&v,&c);
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addedge(u,v,c);
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}
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n=V;
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ans=SAP(1,V);
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dfs1(1);
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dfs2(V);
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for(i=0;i<k;i++)
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a[i]=edge[i].c;
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a1=0,a2=0;
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for(i=2;i<V;i++){
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if(f[i]==1){
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for(j=0;j<k;j++)
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edge[j].c=a[j];
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memset(dis,0,sizeof(dis));
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memset(gap,0,sizeof(gap));
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n=i;
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sap=SAP(1,i);
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a1=max(a1,sap);
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}
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if(f[i]==2){
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for(j=0;j<k;j++)
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edge[j].c=a[j];
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memset(dis,0,sizeof(dis));
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memset(gap,0,sizeof(gap));
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n=V-i+1;
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sap=SAP(i,V);
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a2=max(a2,sap);
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}
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}
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printf("%d\n",ans+min(a1,a2));
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}
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return 0;
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}
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