Submission #3468616

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Source Code Expand

#include<bits/stdc++.h>
#define MAXM 30000010
#define MAXN 51000
#define INF 0x3f3f3f3f
using namespace std;
struct int_Edge
{
    int u,v;
    int w;
    double cost;
    int next;
}Edge[MAXM];
int dis[MAXN],head[MAXN],pre[MAXN],cnt_Edge=1,Maxf_S,Maxf_T;
inline void Insert_Edge(int u,int v,int w,double cost)
{
    ++cnt_Edge;Edge[cnt_Edge].u=u;Edge[cnt_Edge].v=v;Edge[cnt_Edge].w=w;Edge[cnt_Edge].cost= cost;Edge[cnt_Edge].next=head[u];head[u]=cnt_Edge;
    ++cnt_Edge;Edge[cnt_Edge].u=v;Edge[cnt_Edge].v=u;Edge[cnt_Edge].w=0;Edge[cnt_Edge].cost=-cost;Edge[cnt_Edge].next=head[v];head[v]=cnt_Edge;
}
bool vis[MAXN];
double h[MAXN];
inline bool MCMFSPFA()
{
    static int v;
    for(int i=1;i<MAXN;i++)
        h[i]=1e9+7;
    memset(pre,-1,sizeof(pre));
    h[Maxf_S]=0;
    queue<int>q;
    q.push(Maxf_S);
    while(!q.empty())
    {
        int u=q.front();q.pop();
        vis[u]=false;
        for(register int i=head[u];i;i=Edge[i].next)
        {
            v=Edge[i].v;
            if((h[v]>h[u]+Edge[i].cost)&&Edge[i].w>0)
            {
                h[v]=h[u]+Edge[i].cost;
                pre[v]=i;
                if(!vis[v])
                {
                    vis[v]=true;
                    q.push(v);
                }
            }
        }
    }
    return pre[Maxf_T]!=-1;
}
int MAX_FLOW=0;
double MIN_COST=0.0000000;
inline void MCMF()
{
    while(MCMFSPFA())
    {
        int delt=0x3f3f3f3f;
        double coss=0;
        for(register int i=Maxf_T;i!=Maxf_S;i=Edge[pre[i]].u)
            delt=min(delt,Edge[pre[i]].w);
        for(register int i=Maxf_T;i!=Maxf_S;i=Edge[pre[i]].u)
        {
            Edge[pre[i]].w-=delt;
            Edge[pre[i]^1].w+=delt;
            coss+=Edge[pre[i]].cost;
        }

        MAX_FLOW+=delt;
        MIN_COST+=(coss*delt);
    }
}
double x[MAXN],y[MAXN];
int main()
{
    int n;
    scanf("%d",&n);
    int SS=n*2+2,TT=n*2+3,TTT=n*3+4;
    for(int i=1;i<=n;i++)scanf("%lf%lf",&x[i],&y[i]);
    for(int i=1;i<=n;i++)
    {
        Insert_Edge(SS,i,1,0.0000000);
        Insert_Edge(i+n,TT,1,0);
        Insert_Edge(i,i+n,1,abs(x[i]));
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            if(i==j)
                continue;
            Insert_Edge(i,j+n,1,sqrt((x[i]+x[j])*(x[i]+x[j])+(y[i]-y[j])*(y[i]-y[j]))/2);
        }
    }
    Insert_Edge(TT,TTT,n,0.0000000);
    Maxf_S=SS;
    Maxf_T=TTT;
    MCMF();
    printf("%.7f",MIN_COST);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:76:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
./Main.cpp:78:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++)scanf("%lf%lf",&x[i],&y[i]);
                                                     ^

Judge Result