#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#include<numeric>
#include<cmath>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
class Edge
{
public:
int from,to, flow, capacity;
Edge(const int &v,const int &a, const int &c,const int &f)
{
from=v,to = a, capacity = c,flow=f;
}
};
class Network
{
private:
int n, m;//表示頂點個數和邊個數
int src, sink;//表示源點和匯點
int max_flow;//最大流
vector<Edge>edge;//邊數的兩倍
vector<vector<int>>adjList;//鄰接表
public:
void addEdge(const int &from,const int &to,const int &capacity)
{
edge.push_back({from,to,capacity,0});
adjList[from].push_back(edge.size()-1);
edge.push_back({to,from,0,0});
adjList[from].push_back(edge.size() - 1);
}
Network(const int &N)
{
max_flow = 0,n = N;
cin >> src >> sink >> m;
adjList.resize(n + 1);
for (int i = 0; i < m; i++)
{
int from, to, capacity;
cin >> from >> to >> capacity;
addEdge(from,to,capacity);
addEdge(to, from, capacity);
}
}
void getMaxFlow()
{
vector<int>path(n + 1);
while (1)
{
vector<int>augument(n + 1);
queue<int>Q;
Q.push(src);
augument[src] = 2000000000;
while (!Q.empty())
{
auto x = Q.front();
Q.pop();
for (int i = 0; i < adjList[x].size(); i++)
{
Edge&e = edge[adjList[x][i]];
if (!augument[e.to]&&e.capacity>e.flow)
{
path[e.to] = adjList[x][i];
augument[e.to] = std::min(augument[x],e.capacity-e.flow);
Q.push(e.to);
}
}
if (augument[sink])
{
break;
}
}
if (!augument[sink])
{
break;
}
for (auto u = sink;u!=src;u=edge[path[u]].from)
{
edge[path[u]].flow += augument[sink];
edge[path[u]^1].flow-= augument[sink];
}
max_flow += augument[sink];
}
}
void printMaxFlow()
{
cout << "The bandwidth is " << max_flow << "." << endl<<endl;
}
};
int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
int count = 0,n;
while (cin >> n&&n)
{
cout << "Network " << ++count << endl;
Network network(n);
network.getMaxFlow();
network.printMaxFlow();
}
return 0;
}
#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#include<numeric>
#include<cmath>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
const int infinity =1000000000;
class Network
{
private:
int vexnum, edgenum, maxflow, source, destination;
vector<int>remnant, path;
vector<vector<int>>flow, capacity;
public:
void addEdge()
{
int from, to, c; cin >> from >> to >> c;
capacity[from - 1][to - 1] += c;
capacity[to - 1][from - 1] += c;
}
Network(const int &n)
{
vexnum = n;
cin >> source >> destination >> edgenum;
source--, destination--;
flow.resize(vexnum, (vector<int>)vexnum), capacity.resize(vexnum, (vector<int>)vexnum);//最開始每條邊的流量都是0
for (int i = 0; i < edgenum; i++)
{
addEdge();
}
}
void getMaxFlow_EK()
{
maxflow = 0;
queue<int> Q;
while (!Q.empty())
{
Q.pop();
}
vector<int>path(vexnum);
while (true)
{
vector<int>remnant(vexnum);//殘餘流量得變0,一開始所有點都沒流入對吧
remnant[source] = infinity; //源點嘛,剩餘流量無限是必須的...
Q.push(source); //從源點開始進行BFS找增廣路
int from, to;
while (!Q.empty())
{
from = Q.front();Q.pop();
for (to = 0; to < vexnum; to++)//遍歷所有點,找可行邊
{
if (!remnant[to] && capacity[from][to]>flow[from][to])
{ //該點剩餘流量爲0 且 容量大於流量,也就是找到了新的結點
path[to] = from; //找到新結點,父節點得記錄一下吧
Q.push(to);
remnant[to] = std::min(remnant[from], capacity[from][to] - flow[from][to]); //如果u的剩餘流量能填滿uv就填滿,不能的話就把u這點的流量全部流向uv
}
}
}
if (remnant[destination] == 0) //如果當前已經是最大流,匯點沒有殘餘流量
{
break;
}
for (from = destination; from != source; from = path[from])
{ //如果還能增廣,那麼回溯,從匯點往回更新每條走過的邊的流量
flow[path[from]][from] += remnant[destination]; //更新正向流量 （注意這裏更新的是流量，而不是容量）
flow[from][path[from]] -= remnant[destination]; //更新反向流量
}
maxflow += remnant[destination];
}
}
void print()
{
cout << "The bandwidth is " << maxflow << "." << endl<<endl;
}
};
int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
int n,count=0;
while (cin>>n&&n)
{
cout << "Network " << ++count << endl;
Network network(n);
network.getMaxFlow_EK();
network.print();
}
return 0;
}
<pre name="code" class="cpp">#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#include<numeric>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
const int MaxVexNum = 1000;
const int INF = 1000000000;
class Edge
{
public:
int to, capacity, flow;
Edge(int t, int c, int f)
{
to = t,capacity = c,flow = f;
}
};
class Network
{
private:
int vexnum, edgenum, source, destination,maxflow;
vector<vector<Edge>>adjList;
public:
void addEdge(int from, int to, int cap)
{
adjList[from].push_back({ to, cap, (int)adjList[to].size() });
adjList[to].push_back({ from, 0, (int)adjList[from].size() - 1 });
}
Network()
{
adjList.resize(MaxVexNum);
cin >> vexnum >> source >> destination >> edgenum;
for (int i = 0; i < edgenum; i++)
{
int from, to, capacity;
cin >> from >> to >> capacity;
addEdge(from, to, capacity);
addEdge(to, from, capacity);
}
}
int dfs(int src, int sink, int flow,vector<bool>&used)
{
if (src == sink)
{
return flow;
}
used[src] = true;
for (int i = 0; i<adjList[src].size(); i++)
{
Edge &edge = adjList[src][i];
if (!used[edge.to] && edge.capacity>0)
{
int minflow = dfs(edge.to, sink, std::min(flow, edge.capacity),used);
if (minflow>0)
{
edge.capacity -= minflow;
adjList[edge.to][edge.flow].capacity += minflow;
return minflow;
}
}
}
return 0;
}
void getMaxFlow()
{
maxflow = 0;
while (1)
{
vector<bool>used(MaxVexNum);
int f = dfs(source, destination, INF,used);
if (!f)
{
return;
}
maxflow += f;
}
}
void print()
{
cout << "The bandwidth is " << maxflow << '.' << endl<<endl;
}
};
int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
char ch; int count = 0;
while ((ch=cin.get())!='0')
{
printf("Network %d\n", ++count);
ungetc(ch,stdin);
Network network;
network.getMaxFlow();
network.print();
cin.get();
}
return 0;
}
