Hdu3829_cat vs dog

The question is, given that some people like a cat or a dog, they hate a cat or a dog. How many people wish to be satisfied at most?

The question is very interesting. After modeling, it is easy.

If one cat or dog is annoying and another person prefers it, the two are connected to one side. Finally, the maximum number of independent sets is equal to the maximum number of matches ..

Orz.

 

Summon code:

 

#include <iostream>#include <cstdio>#include <cstring>#include <vector>#define maxn 505using namespace std;vector<int> likec[maxn],disc[maxn],liked[maxn],disd[maxn];vector<int> v[maxn];int n,m,p,ans,t1,t2;int f[maxn],tag[maxn];char s1[maxn],s2[maxn];void init(){ans=0;for (int i=1; i<=p; i++) v[i].clear(),f[i]=0,tag[i]=0;for (int i=1; i<=n; i++) likec[i].clear(),disc[i].clear();for (int i=1; i<=m; i++) liked[i].clear(),disd[i].clear();}int num(char S[]){int cur=0;for (int i=0; S[i]; i++) cur=cur*10+S[i]-‘0‘;return cur;}int dfs(int cur,int T){if (tag[cur]==T) return false;else tag[cur]=T;for (unsigned i=0; i<v[cur].size(); i++){if (tag[v[cur][i]]==T) continue;if (f[v[cur][i]]==0 || dfs(f[v[cur][i]],T)){f[v[cur][i]]=cur;f[cur]=v[cur][i];return true;}}return false;}int main(){while (scanf("%d%d%d",&n,&m,&p)!=EOF){init();for (int i=1; i<=p; i++){scanf("%s%s",s1,s2);t1=num(s1+1),t2=num(s2+1);if (s1[0]==‘C‘) likec[t1].push_back(i);else liked[t1].push_back(i);if (s2[0]==‘C‘) disc[t2].push_back(i);else disd[t2].push_back(i);}for (int i=1; i<=n; i++)for (unsigned x1=0; x1<likec[i].size(); x1++)for (unsigned x2=0; x2<disc[i].size(); x2++){v[likec[i][x1]].push_back(disc[i][x2]);v[disc[i][x2]].push_back(likec[i][x1]);}for (int i=1; i<=m; i++)for (unsigned x1=0; x1<liked[i].size(); x1++)for (unsigned x2=0; x2<disd[i].size(); x2++){v[liked[i][x1]].push_back(disd[i][x2]);v[disd[i][x2]].push_back(liked[i][x1]);}for (int i=1; i<=p; i++){if (f[i]!=0) continue;if (dfs(i,i)) ans++;}printf("%d\n",p-ans);}return 0;}