ISAP
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn = 1e5+11;
const int oo = 0x7fffffff;
int to[maxn<<1],nxt[maxn<<1],cap[maxn<<1],flow[maxn<<1];
int head[maxn],tot;
void init(){
memset(head,-1,sizeof head);
tot=0;
}
void add(int u,int v,int w){
to[tot]=v;
nxt[tot]=head[u];
cap[tot]=w;
flow[tot]=0;
head[u]=tot++;
swap(u,v);
to[tot]=v;
nxt[tot]=head[u];
cap[tot]=w;
flow[tot]=0;
head[u]=tot++;
}
int n,m,s,t;
int gap[maxn],dep[maxn],que[maxn];
int cur[maxn],stk[maxn];
void bfs(){
memset(dep,-1,sizeof dep);
memset(gap,0,sizeof gap);
gap[0]=1;
int front=0,rear=0;
que[rear++]=t;dep[t]=0;
while(front^rear){
int u = que[front++];
for(int i = head[u]; ~i; i = nxt[i]){
int v=to[i];
if(~dep[v])continue;
que[rear++]=v;
dep[v]=dep[u]+1;
gap[dep[v]]++;
}
}
}
int isap(){
bfs();
memcpy(cur,head,sizeof head);
int ans=0,top=0,u=s;
while(dep[s]<n){
if(u==t){
int mn=oo;
int inser;
for(int i = 0; i < top; i++){
if(mn>cap[stk[i]]-flow[stk[i]]){
mn=cap[stk[i]]-flow[stk[i]];
inser=i;
}
}
for(int i = 0; i < top; i++){
flow[stk[i]]+=mn;
flow[stk[i]^1]-=mn;
}
ans+=mn;
top=inser;
u=to[stk[top]^1];
continue;
}
bool flag=0;
int v;
for(int i = cur[u]; ~i; i = nxt[i]){
v=to[i];
if(cap[i]-flow[i]&&dep[v]+1==dep[u]){
flag=1;
cur[u]=i;
break;
}
}
if(flag){
stk[top++]=cur[u];
u=v;
continue;
}
int mn=n;
for(int i = head[u]; ~i; i = nxt[i]){
if(cap[i]-flow[i]&&dep[to[i]]<mn){
mn=dep[to[i]];
cur[u]=i;
}
}
gap[dep[u]]--;
if(!gap[dep[u]])return ans;
dep[u]=mn+1;
gap[dep[u]]++;
if(u!=s)u=to[stk[--top]^1];
}
return ans;
}
MCMF
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn = 1e5+11;
const int oo = 0x3f3f3f3f;
int to[maxn<<1],cost[maxn<<1],cap[maxn<<1],flow[maxn<<1],nxt[maxn<<1];
int head[maxn],tot;
void init(){
memset(head,-1,sizeof head);
tot=0;
}
void add(int u,int v,int c,int w){
to[tot]=v;
cap[tot]=c;
flow[tot]=0;
cost[tot]=w;
nxt[tot]=head[u];
head[u]=tot++;
swap(u,v);
to[tot]=v;
cap[tot]=0;
flow[tot]=0;
cost[tot]=-w;
nxt[tot]=head[u];
head[u]=tot++;
}
struct QUEUE{
int que[maxn];
int front,rear;
void init(){front=rear=0;}
void push(int x){que[rear++]=x;}
int pop(){return que[front++];}
bool empty(){return front==rear;}
}que;
int n,m,s,t;
bool vis[maxn];
int pre[maxn],dis[maxn];
bool spfa(){
que.init();
memset(vis,0,sizeof vis);
memset(pre,-1,sizeof pre);
memset(dis,oo,sizeof dis);
que.push(s);vis[s]=1;dis[s]=0;
while(!que.empty()){
int u=que.pop(); vis[u]=0;
for(int i = head[u]; ~i; i = nxt[i]){
int v=to[i],c=cap[i],f=flow[i],w=cost[i];
if(c>f&&dis[v]>dis[u]+w){
dis[v]=dis[u]+w;
pre[v]=i;
if(!vis[v]){
que.push(v);
vis[v]=1;
}
}
}
}
if(dis[t]==oo) return 0;
else return 1;
}
int mcmf(){
int mc=0,mf=0;
while(spfa()){
int tf=oo+1;
for(int i = pre[t]; ~i; i = pre[to[i^1]]){
tf=min(tf,cap[i]-flow[i]);
}
mf+=tf;
for(int i = pre[t]; ~i; i = pre[to[i^1]]){
flow[i]+=tf;
flow[i^1]-=tf;
}
mc+=dis[t]*tf;
}
return mc;
}
ISAP2.0
#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e5+11;
const int oo = 0x7fffffff;
int to[maxn<<1],nxt[maxn<<1],cap[maxn<<1],flow[maxn<<1];
int head[maxn],tot;
void init(){
memset(head,-1,sizeof head);
tot=0;
}
void add(int u,int v,int w){
to[tot]=v;
nxt[tot]=head[u];
cap[tot]=w;
flow[tot]=0;
head[u]=tot++;
swap(u,v);
to[tot]=v;
nxt[tot]=head[u];
cap[tot]=0;
flow[tot]=0;
head[u]=tot++;
}
int n,m,s,t;
int dis[maxn],pre[maxn],cur[maxn],gap[maxn];
bool vis[maxn];
struct QUEUE{
int que[maxn];
int front,rear;
void init(){front=rear=0;}
void push(int u){que[rear++]=u;}
int pop(){return que[front++];}
bool empty(){return front==rear;}
}que;
void bfs(){
memset(vis,0,sizeof vis);
que.init();
que.push(t);
vis[t]=1;dis[t]=0;
while(que.empty()^1){
int u = que.pop();
for(int i = head[u]; ~i; i = nxt[i]){
register int v=to[i],c=cap[i^1],f=flow[i^1];
if(!vis[v]&&c>f){
vis[v]=1;
dis[v]=dis[u]+1;
que.push(v);
}
}
}
}
int aug(){
int u=t,ans=oo;
while(u!=s){
ans=min(ans,cap[pre[u]]-flow[pre[u]]);
u=to[pre[u]^1];
}
u=t;
while(u!=s){
flow[pre[u]]+=ans;
flow[pre[u]^1]-=ans;
u=to[pre[u]^1];
}
return ans;
}
int isap(){
int ans=0;
bfs();
memset(gap,0,sizeof gap);
memcpy(cur,head,sizeof head);
for(int i = 1; i <= n; i++) gap[dis[i]]++;
int u = s;
while(dis[s]<n){
if(u==t){
ans+=aug();
u=s;
}
bool ok=0;
for(int i = cur[u]; ~i; i = nxt[i]){
int v=to[i],c=cap[i],f=flow[i];
if(c>f&&dis[u]==dis[v]+1){
ok=1;
pre[v]=i;
cur[u]=i;
u=v;
break;
}
}
if(!ok){
int mn=n-1;
for(int i = head[u]; ~i; i = nxt[i]){
int v=to[i],c=cap[i],f=flow[i];
if(c>f) mn=min(mn,dis[v]);
}
if(--gap[dis[u]]==0) break;
dis[u]=mn+1;gap[dis[u]]++;cur[u]=head[u];
if(u!=s) u=to[pre[u]^1];
}
}
return ans;
}