hdu 1532 求1~n的最大流
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
using namespace std;const int MAXN = ; //点数的最大值
const int MAXM = ; //边数的最大值
const int INF = 0x3f3f3f3f;struct Node
{
int from, to, next;
int cap;
} edge[MAXM];
int tol;
int head[MAXN];
int dep[MAXN];
int gap[MAXN];//gap[x]=y :说明残留网络中dep[i]==x的个数为yint n;//n是总的点的个数，包括源点和汇点void init()
{
tol = ;
memset(head, -, sizeof(head));
}void addedge(int u, int v, int w)
{
edge[tol].from = u;
edge[tol].to = v;
edge[tol].cap = w;
edge[tol].next = head[u];
head[u] = tol++;
edge[tol].from = v;
edge[tol].to = u;
edge[tol].cap = ;
edge[tol].next = head[v];
head[v] = tol++;
}
void BFS(int start, int end)
{
memset(dep, -, sizeof(dep));
memset(gap, , sizeof(gap));
gap[] = ;
int que[MAXN];
int front, rear;
front = rear = ;
dep[end] = ;
que[rear++] = end;
while (front != rear)
{
int u = que[front++];
if (front == MAXN)
{
front = ;
}
for (int i = head[u]; i != -; i = edge[i].next)
{
int v = edge[i].to;
if (dep[v] != -)
{
continue;
}
que[rear++] = v;
if (rear == MAXN)
{
rear = ;
}
dep[v] = dep[u] + ;
++gap[dep[v]];
}
}
}
int SAP(int start, int end)
{
int res = ;
BFS(start, end);
int cur[MAXN];
int S[MAXN];
int top = ;
memcpy(cur, head, sizeof(head));
int u = start;
int i;
while (dep[start] < n)
{
if (u == end)
{
int temp = INF;
int inser;
for (i = ; i < top; i++)
if (temp > edge[S[i]].cap)
{
temp = edge[S[i]].cap;
inser = i;
}
for (i = ; i < top; i++)
{
edge[S[i]].cap -= temp;
edge[S[i] ^ ].cap += temp;
}
res += temp;
top = inser;
u = edge[S[top]].from;
}
if (u != end && gap[dep[u] - ] == ) //出现断层，无增广路
{
break;
}
for (i = cur[u]; i != -; i = edge[i].next)
if (edge[i].cap != && dep[u] == dep[edge[i].to] + )
{
break;
}
if (i != -)
{
cur[u] = i;
S[top++] = i;
u = edge[i].to;
}
else
{
int min = n;
for (i = head[u]; i != -; i = edge[i].next)
{
if (edge[i].cap == )
{
continue;
}
if (min > dep[edge[i].to])
{
min = dep[edge[i].to];
cur[u] = i;
}
}
--gap[dep[u]];
dep[u] = min + ;
++gap[dep[u]];
if (u != start)
{
u = edge[S[--top]].from;
}
}
}
return res;
}int main()
{
// freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
int start, end;
int m;
int u, v, z;
int T;
while (~scanf("%d%d", &m, &n))
{
init();
while (m--)
{
scanf("%d%d%d", &u, &v, &z);
addedge(u, v, z);
//addedge(v, u, z);
}
//n一定是点的总数，这是使用SAP模板需要注意的
int ans = SAP(, n);
printf("%d\n", ans);
}
return ;
}
hdu 4280 给你岛的坐标求最西边到最东边的最大流
/*
最大流模板
sap
*/
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
using namespace std;const int MAXN=;//点数的最大值
const int MAXM=;//边数的最大值
const int INF=0x3f3f3f3f;struct Node
{
int from,to,next;
int cap;
}edge[MAXM];
int tol;
int head[MAXN];
int dep[MAXN];
int gap[MAXN];//gap[x]=y :说明残留网络中dep[i]==x的个数为yint n;//n是总的点的个数，包括源点和汇点void init()
{
tol=;
memset(head,-,sizeof(head));
}void addedge(int u,int v,int w)
{
edge[tol].from=u;
edge[tol].to=v;
edge[tol].cap=w;
edge[tol].next=head[u];
head[u]=tol++;
edge[tol].from=v;
edge[tol].to=u;
edge[tol].cap=;
edge[tol].next=head[v];
head[v]=tol++;
}
void BFS(int start,int end)
{
memset(dep,-,sizeof(dep));
memset(gap,,sizeof(gap));
gap[]=;
int que[MAXN];
int front,rear;
front=rear=;
dep[end]=;
que[rear++]=end;
while(front!=rear)
{
int u=que[front++];
if(front==MAXN)front=;
for(int i=head[u];i!=-;i=edge[i].next)
{
int v=edge[i].to;
if(dep[v]!=-)continue;
que[rear++]=v;
if(rear==MAXN)rear=;
dep[v]=dep[u]+;
++gap[dep[v]];
}
}
}
int SAP(int start,int end)
{
int res=;
BFS(start,end);
int cur[MAXN];
int S[MAXN];
int top=;
memcpy(cur,head,sizeof(head));
int u=start;
int i;
while(dep[start]<n)
{
if(u==end)
{
int temp=INF;
int inser;
for(i=;i<top;i++)
if(temp>edge[S[i]].cap)
{
temp=edge[S[i]].cap;
inser=i;
}
for(i=;i<top;i++)
{
edge[S[i]].cap-=temp;
edge[S[i]^].cap+=temp;
}
res+=temp;
top=inser;
u=edge[S[top]].from;
}
if(u!=end&&gap[dep[u]-]==)//出现断层，无增广路
break;
for(i=cur[u];i!=-;i=edge[i].next)
if(edge[i].cap!=&&dep[u]==dep[edge[i].to]+)
break;
if(i!=-)
{
cur[u]=i;
S[top++]=i;
u=edge[i].to;
}
else
{
int min=n;
for(i=head[u];i!=-;i=edge[i].next)
{
if(edge[i].cap==)continue;
if(min>dep[edge[i].to])
{
min=dep[edge[i].to];
cur[u]=i;
}
}
--gap[dep[u]];
dep[u]=min+;
++gap[dep[u]];
if(u!=start)u=edge[S[--top]].from;
}
}
return res;
}int main()
{
// freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
int start,end;
int m;
int u,v,z;
int T;
scanf("%d",&T); while(T--)
{
init();
scanf("%d%d",&n,&m);
int minx=;
int maxx=-;
int x,y;
for(int i=;i<=n;i++)
{
scanf("%d%d",&x,&y);
if(minx>x)
{
minx=x;
start=i;
}
if(maxx<x)
{
maxx=x;
end=i;
}
} while(m--)
{
scanf("%d%d%d",&u,&v,&z);
addedge(u,v,z);
addedge(v,u,z);
}
//n一定是点的总数，这是使用SAP模板需要注意的
int ans=SAP(start,end);
printf("%d\n",ans);
}
return ;
}
