【模板整合】匈牙利算法和Hopcroft-Karp算法

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#define MAXN 1010
using namespace std;
int n,m;
int map[MAXN][MAXN],num[MAXN];
bool vis[MAXN];
int ans;
bool find(int x)
{
for (int i=1;i<=n;i++)
{
if (!vis[i]&&map[x][i])
{
vis[i]=1;
if (!num[i]||find(num[i]))
{
num[i]=x;
return 1;
}
}
}
return 0;
}
int main()
{
scanf("%d%d",&n,&m);
/*for (int i=1;i<=m;i++)
{
int x,y;
scanf("%d%d",&x,&y);x++;y++;
map[i][x]=map[i][y]=1;
}建图请自动忽略*/
for (int i=1;i<=m;i++)
{
memset(vis,0,sizeof(vis));
if (find(i))    ans++;
else    break;
}
printf("%d\n",ans);
}

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<queue>
#define MAXN 1010
#define MAXINT 0x7fffffff
using namespace std;
int n,m,top,x,y;
int ans;
int disx[MAXN],disy[MAXN],matx[MAXN],maty[MAXN];//x,y,分别为二分图的两个点集,mat为每个点在对侧集合的匹配点,如果当前没有匹配点则为-1
struct edge
{
int to;
edge *next;
}e[MAXN*MAXN],*prev[MAXN];
void insert(int u,int v)
{
e[++top].to=v;e[top].next=prev[u];prev[u]=&e[top];
}
bool bfs()//寻找最短增广路
{
bool ret=0;
queue<int> q;
memset(disx,0,sizeof(disx));memset(disy,0,sizeof(disy));
for (int i=1;i<=n;i++)
if (matx[i]==-1)    q.push(i);//找到未盖点,入队
while (!q.empty())//在二分图另一个点集的非盖点中寻找增广路
{
int x=q.front();q.pop();
for (edge *i=prev[x];i;i=i->next)
if (!disy[i->to])
{
disy[i->to]=disx[x]+1;
if (maty[i->to]==-1)    ret=1;//找到增广路
else    disx[maty[i->to]]=disy[i->to]+1,q.push(maty[i->to]);
}
}
return ret;
}
bool dfs(int x)//沿增广路增广
{
for (edge *i=prev[x];i;i=i->next)
{
if (disy[i->to]==disx[x]+1)
{
disy[i->to]=0;
if (maty[i->to]==-1||dfs(maty[i->to]))
{
matx[x]=i->to;maty[i->to]=x;return 1;
}
}
}
return 0;
}
int main()
{
scanf("%d%d",&n,&m);
memset(matx,-1,sizeof(matx));memset(maty,-1,sizeof(maty));
/*for (int i=1;i<=n;i++)
{
scanf("%d%d",&x,&y);x++;y++;
insert(i,x);insert(i,y);
}建图请自动忽略*/
while (bfs())
{
for (int i=1;i<=m;i++)
if (matx[i]==-1&&dfs(i))    ans++;
}
cout<<ans<<endl;
}