HDU 2767 Strong Unicom components

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Test instructions: Ask how many sides the graph will become a strong unicom component of 1 figure

Train of thought: simple strong unicom, shrink point after looking into the degree and out of the line, water problem

#include <vector> #include <stdio.h> #include <string.h> #include <stdlib.h> #include < Iostream> #include <algorithm>using namespace std;typedef long long ll;const int Inf=0x3f3f3f3f;const int maxn= 20010;vector<int> g[maxn];vector<int> rg[maxn];vector<int> vs;bool used[maxn];int Cmp[maxn],V;    void Add_edge (int from,int to) {g[from].push_back (to); Rg[to].push_back (from);}    void Dfs (int v) {used[v]=1;    for (int i=0;i<g[v].size (); i++) {if (!used[g[v][i])) DFS (G[v][i]); } vs.push_back (v);}    void Rdfs (int v,int k) {used[v]=1;    Cmp[v]=k;    for (int i=0;i<rg[v].size (); i++) {if (!used[rg[v][i]) Rdfs (rg[v][i],k);    }}int SCC () {memset (used,0,sizeof (used));    Vs.clear ();    for (int v=0;v<v;v++) if (!used[v]) Dfs (v);    memset (used,0,sizeof (used));    int k=0;    for (int i=vs.size () -1;i>=0;i--) {if (!used[vs[i]) Rdfs (vs[i],k++); } return k;} int A[maxn*3],b[maxn*3];int In[maxn],out[maxn];int mAin () {int t,m;    scanf ("%d", &t);        while (t--) {scanf ("%d%d", &v,&m);        memset (In,0,sizeof (in));        Memset (out,0,sizeof (out));            for (int i=0;i<maxn;i++) {g[i].clear ();        Rg[i].clear ();        } vs.clear ();            for (int i=0;i<m;i++) {scanf ("%d%d", &a[i],&b[i]); a[i]--;            b[i]--;        Add_edge (A[i],b[i]);        } int ANS=SCC ();            if (ans==1) {printf ("0\n");        Continue            } for (int i=0;i<m;i++) {int a=cmp[a[i]],b=cmp[b[i]];            if (a!=b) {in[b]++;out[a]++;        }} int sum1=0,sum2=0;            for (int i=0;i<ans;i++) {if (in[i]==0) sum1++;        if (out[i]==0) sum2++;    } printf ("%d\n", Max (sum1,sum2)); } return 0;}

HDU 2767 Strong Unicom components