套的Dinic模板，权当测模板了~
1 #include<cstdio> 2 #include<cmath> 3 #include<cstring> 4 #include<algorithm> 5 #include<map> 6 #include<queue> 7 #include<set> 8 #include<vector> 9 #include<iostream> 10 #define PB push_back 11 #define POB pop_back 12 #define PII pair<int, int> 13 #define PDD pair<double, double> 14 #define rep(i, a, b) for(int i = a ; i < b ; i++) 15 #pragma comment(linker, "/STACK:1024000000,1024000000") 16 #pragma GCC push_options 17 #pragma GCC optimize ("Os") 18 #pragma loop_opt(on) 19 #ifdef WIN32 20 #define INT64 "%I64d" 21 #define UINT64 "%I64u" 22 #else 23 #define INT64 "%lld" 24 #define UINT64 "%llu" 25 #endif 26 typedef long long LL; 27 typedef unsigned long long ULL; 28 using namespace std; 29 const int INF = 0x3f3f3f3f; 30 const int maxn = 110; 31 struct Edge { 32 int from, to, cap, flow; 33 Edge(int from, int to, int cap, int flow) : from(from), to(to), cap(cap), flow(flow) {} 34 }; 35 struct Dinic { 36 int n, m, s, t; 37 vector<Edge> edges; 38 vector<int> G[maxn]; 39 bool vis[maxn]; 40 int d[maxn]; 41 int cur[maxn]; 42 void AddEdge(int from, int to, int cap) { 43 edges.PB(Edge(from, to, cap, 0)); 44 edges.PB(Edge(from, to, 0, 0)); 45 m = edges.size(); 46 G[from].PB(m - 2); 47 G[to].PB(m - 1); 48 } 49 50 bool BFS() { 51 memset(vis, 0, sizeof vis); 52 queue<int> Q; 53 Q.push(s); 54 d[s] = 0; 55 vis[s] = 1; 56 while(!Q.empty()) { 57 int x = Q.front(); Q.pop(); 58 for(int i = 0 ; i < (int)G[x].size() ; i++) { 59 Edge& e = edges[G[x][i]]; 60 if(!vis[e.to] && e.cap > e.flow) { 61 vis[e.to] = 1; 62 d[e.to] = d[x] + 1; 63 Q.push(e.to); 64 } 65 } 66 } 67 return vis[t]; 68 } 69 70 int DFS(int x, int a) { 71 if(x == t || a == 0) return a; 72 int flow = 0, f; 73 for(int& i = cur[x] ; i <(int)G[x].size() ; i++) { 74 Edge& e = edges[G[x][i]]; 75 if(d[x] + 1 == d[e.to] && (f = DFS(e.to, min(a, e.cap - e.flow))) > 0) { 76 e.flow += f; 77 edges[G[x][i] ^ 1].flow -= f; 78 flow += f; 79 a -= f; 80 if(a == 0) break; 81 } 82 } 83 return flow; 84 } 85 int MaxFlow(int s, int t) { 86 this->s = s; 87 this->t = t; 88 int flow = 0; 89 while(BFS()) { 90 memset(cur, 0, sizeof cur); 91 flow += DFS(s, INF); 92 } 93 return flow; 94 } 95 96 void init() { 97 edges.clear(); 98 for(int i = 0 ; i < maxn ; i++) G[i].clear(); 99 memset(d, 0, sizeof d); 100 } 101 } dinic; 102 int main() 103 { 104 int n; 105 int ca = 1; 106 while(scanf("%d", &n) == 1 && n) { 107 dinic.init(); 108 int a, b, m; scanf("%d%d%d" ,&a, &b, &m); 109 int from, to, cap; 110 for(int i = 0 ; i < m ; i++) scanf("%d%d%d", &from, &to, &cap), dinic.AddEdge(from, to, cap), dinic.AddEdge(to, from, cap); 111 printf("Network %d ", ca++); 112 printf("The bandwidth is %d. ", dinic.MaxFlow(a, b)); 113 } 114 return 0; 115 }