hdu1532(最大流裸题)

题意：

裸的最大流。

思路：

先试了一下红书模板，TLE了，想起来那个比较快的模板，直接就过了。。。果然模板的质量也是不一样的。

代码：

#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<cmath>#include<cstdlib>#include<climits>#include<queue>#include<stack>#include<set>#include<string>#include<vector>using namespace std;const int maxn = 510, maxm = maxn * maxn;const int inf = 1000000000;class MaxFlow//一个挺快的模板,比一般的MaxFlow快,我也不知道为什么。。。{private:    int next[maxm*2];    int num[maxm*2];    int a[maxn*2];    int row_sum[maxn];    int col_sum[maxn];    int n , m, K;    int d[maxn*2], st[maxn*2], cod[maxn][maxn];    int h[maxn*2], vh[maxn*2];    bool don[maxm*2],in[maxn*2];    int dfs(int, int);    bool visit(int, int);public:    int T;    int r[maxm*2];    MaxFlow() {}    int Addedge(int, int, int);    int Run();    bool FindCircle();    void Init(int m)    {        memset(a, 0, sizeof(a));        tt = 1;        T = m;    }    int tt;    ~MaxFlow() {}} mf;int MaxFlow::Addedge(int x,int y,int rr){    next[++tt]=a[x];    num[tt]=y;    r[tt]=rr;    a[x]=tt;    next[++tt]=a[y];    num[tt]=x;    r[tt]=0;    a[y]=tt;    return tt;}int MaxFlow::dfs(int x,int y){    if (x==T) return y;    int sig=st[x],minh=T+1;    do    {        if (r[st[x]])        {            if (h[num[st[x]]]+1==h[x])            {                int k=dfs(num[st[x]],min(y,r[st[x]]));                if (k)                {                    r[st[x]]-=k;                    r[st[x]^1]+=k;                    return k;                }            }            minh=min(minh,h[num[st[x]]]+1);            if (h[0]>T) return 0;        }        st[x]=next[st[x]];        if (st[x]==0) st[x]=a[x];    }    while (sig!=st[x]);    if (vh[h[x]]--==0) h[0]=T+1;    vh[h[x]=minh]++;    return 0;}int MaxFlow::Run(){    for (int i=0; i<=T; i++) h[i]=vh[i]=0;    for (int i=0; i<=T; i++) st[i]=a[i];    vh[0]=T+1;    int ret=0;    while (h[0]<=T) ret+=dfs(0,K+1);    return ret;}bool MaxFlow::visit(int x,int ed){    if (don[ed])        return in[x];    don[ed]=true;    in[x]=true;    for (int p=a[x]; p; p=next[p])    {        if (r[p] && (ed^p)!=1)            if (visit(num[p],p)) return true;    }    in[x]=false;    return false;}bool MaxFlow::FindCircle(){    for (int i=0; i<=T; i++) in[i]=false;    for (int i=1; i<=tt; i++) don[i]=false;    for (int i=2; i<=tt; i++)    {        if (r[i] && !don[i])        {            in[num[i^1]]=true;            if (visit(num[i],i)) return true;            in[num[i^1]]=false;        }    }    return false;}int main(){int n,m;while(scanf("%d%d",&n,&m)!=EOF){int t=m;mf.Init(t);mf.Addedge(0,1,inf);for(int i=1;i<=n;i++){int s,t,c;scanf("%d%d%d",&s,&t,&c);mf.Addedge(s,t,c);}int ans=mf.Run();printf("%d\n",ans);}    return 0;}

另附上红书TLE模板：

#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<cmath>#include<cstdlib>#include<climits>#include<queue>#include<stack>#include<set>#include<string>#include<vector>using namespace std;const int maxn = 510, maxm = maxn * maxn;const int inf = 1000000000;struct Edge{int v,f,nxt;};int n,src,sink;int g[maxn+10];int nume;Edge e[maxm*2+10];void addedge(int u,int v,int c){e[++nume].v=v;e[nume].f=c;e[nume].nxt=g[u];g[u]=nume;e[++nume].v=u;e[nume].f=0;e[nume].nxt=g[v];g[v]=nume;}void init(){memset(g,0,sizeof g);nume=1;}queue<int> que;bool vis[maxn+10];int dist[maxn+10];void bfs(){memset(dist ,0,sizeof dist);while(!que.empty())que.pop();vis[src]=true;que.push(src);while(!que.empty()){int u=que.front();que.pop();for(int i=g[u];i;i=e[i].nxt)if(e[i].f&&!vis[e[i].v]){que.push(e[i].v);dist[e[i].v]=dist[u]+1;vis[e[i].v]=true;}}}int dfs(int u,int delta){if(u==sink){return delta;}else {int ret=0;for(int i=g[u];delta&&i; i=e[i].nxt)if(e[i].f&&dist[e[i].v]==dist[u]+1){int dd=dfs(e[i].v,min(e[i].f,delta));e[i].f-=dd;e[i^1].f+=dd;ret+=dd;}return ret;}}int maxflow(){int ret=0;while(true){memset(vis,0,sizeof vis);bfs();if(!vis[sink])return ret;ret+=dfs(src,inf);}}int main(){int n,m;while(scanf("%d%d",&n,&m)!=EOF){init();src=1;sink=m;for(int i=1;i<=n;i++){int s,t,c;scanf("%d%d%d",&s,&t,&c);addedge(s,t,c);}int ans=maxflow();printf("%d\n",ans);}    return 0;}