Dinic：

int tot;int front[N],to[M<<1],nxt[M<<1],val[M<<1];int src,decc;int cur[N],lev[N];queue
     
      q;void read(int &x){    x=0; char c=getchar();    while(!isdigit(c)) { if(c=='-') f=-1; c=getchar(); }     while(isdigit(c)) { x=x*10+c-'0'; c=getchar();  }}void add(int u,int v,int w){    to[++tot]=v; nxt[tot]=front[u]; front[u]=tot; val[tot]=w;    to[++tot]=u; nxt[tot]=front[v]; front[v]=tot; val[tot]=0;}bool bfs(){    while(!q.empty()) q.pop();    for(int i=src;i<=decc;i++) lev[i]=-1,cur[i]=front[i];    lev[src]=0;     q.push(src);    int now;    while(!q.empty())    {        now=q.front(); q.pop();        for(int i=front[now];i;i=nxt[i])        {            if(lev[to[i]]==-1&&val[i]>0)            {                lev[to[i]]=lev[now]+1;                if(to[i]==decc) return true;                q.push(to[i]);            }        }    }    return false;}int dinic(int now,int flow){    if(now==decc) return flow;    int rest=0,delta;    for(int &i=cur[now];i;i=nxt[i])    {        if(lev[to[i]]>lev[now]&&val[i]>0)        {            delta=dinic(to[i],min(flow-rest,val[i]));            if(delta)            {                val[i]-=delta; val[i^1]+=delta;                rest+=delta; if(rest==flow) break;            }        }    }    if(rest==flow) lev[now]=-1;    return rest;}
     

 

isap：

int tot;int front[N],nxt[M<<1],to[M<<1],val[M<<1],from[M<<1];int lev[N],num[N];int path[N];int cur[N]; int src,decc;void add(int u,int v,int w){    to[++tot]=v; nxt[tot]=front[u]; front[u]=tot; from[tot]=u; val[tot]=w;    to[++tot]=u; nxt[tot]=front[v]; front[v]=tot; from[tot]=v; val[tot]=0;}bool bfs(){    queue
     
      q;    for(int i=src;i<=decc;++i) lev[i]=decc;    q.push(decc);    lev[decc]=0;    int now,t;    while(!q.empty())    {        now=q.front();        q.pop();        for(int i=front[now];i;i=nxt[i])        {            t=to[i];            if(lev[t]==decc && val[i^1])             {                lev[t]=lev[now]+1;                q.push(t);            }        }    }    return lev[src]!=decc;} int augment(){    int now=decc,flow=inf;    int i;    while(now!=src)    {        i=path[now];        flow=min(flow,val[i]);        now=from[i];    }    now=decc;    while(now!=src)    {        i=path[now];        val[i]-=flow;        val[i^1]+=flow;        now=from[i];    }    return flow;} int isap(){    int flow=0;    if(!bfs()) return 0;    memset(num,0,sizeof(num));    for(int i=src;i<=decc;++i) num[lev[i]]++,cur[i]=front[i];    int now=src,t;    while(lev[src]<=decc)    {        if(now==decc)        {            flow+=augment();            now=src;        }        bool advanced=false;        for(int i=cur[now];i;i=nxt[i])        {            t=to[i];            if(lev[t]==lev[now]-1 && val[i])            {                advanced=true;                path[t]=i;                cur[now]=i;                now=t;                break;            }        }        if(!advanced)        {            int mi=decc;            for(int i=front[now];i;i=nxt[i])                if(val[i]) mi=min(mi,lev[to[i]]);            if(!--num[lev[now]]) break;            num[lev[now]=mi+1]++;            cur[now]=front[now];            if(now!=src) now=from[path[now]];        }    }    return flow;}