Dinic 鄰接表

（抄襲神牛的板子 傳送門：https://blog.csdn.net/u013480600/article/details/38796521）

代碼：

#include <set> #include <map> #include <queue> #include <stack> #include <math.h> #include <vector> #include <string> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <iostream> #include <algorithm> #define zero(a) fabs(a)<eps #define lowbit(x) (x&(-x)) #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 #define MOD 1000000007 int max(int x,int y){return x>y?x:y;}; int min(int x,int y){return x<y?x:y;}; int max(int x,int y,int z){return max(x,max(y,z));}; int min(int x,int y,int z){return min(x,min(y,z));}; typedef long long LL; const double PI=acos(-1.0); const double eps=1e-8; const int inf=0x3f3f3f3f; const LL linf=0x3f3f3f3f3f3f3f3fLL; using namespace std; int read(){int x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}return x*f; }using namespace std; const int maxn=15+5; const int maxm=2000+10;struct Edge {Edge(){}Edge(int from,int to,int cap,int flow):from(from),to(to),cap(cap),flow(flow){}int from,to,cap,flow; };struct Dinic {int n,m,s,t; //結點數,邊數(包括反向弧),源點與匯點編號Edge edges[maxm]; //邊表 edges[e]和edges[e^1]互為反向弧int head[maxn],next[maxm]; //鄰接表表頭和next數組bool vis[maxn]; //BFS使用,標記一個節點是否被遍歷過int d[maxn]; //從起點到i點的距離int cur[maxn]; //當前弧下標void init(int n,int s,int t){this->n=n,this->s=s,this->t=t;memset(head,-1,sizeof(head));m=0;}void AddEdge(int from,int to,int cap){edges[m]= Edge(from,to,cap,0) ;next[m]=head[from];head[from]=m++;edges[m]= Edge(to,from,0,0) ;next[m]=head[to];head[to]=m++;}bool BFS(){memset(vis,0,sizeof(vis));queue<int> Q;//用來保存節點編號的 Q.push(s);d[s]=0;vis[s]=true;while(!Q.empty()){int x=Q.front(); Q.pop();for(int i=head[x]; i!=-1; i=next[i]){Edge& e=edges[i];if(!vis[e.to] && e.cap>e.flow){vis[e.to]=true;d[e.to] = d[x]+1;Q.push(e.to);}}}return vis[t];}int DFS(int x,int a){if(x==t || a==0)return a;int flow=0,f;//flow用來記錄從x到t的最小殘量for(int& i=cur[x]; i!=-1; i=next[i]){Edge& e=edges[i];if(d[x]+1==d[e.to] && (f=DFS( e.to,min(a,e.cap-e.flow) ) )>0 ){e.flow +=f;edges[i^1].flow -=f;flow += f;a -= f;if(a==0) break;}}return flow;}int Maxflow(){int flow=0;while(BFS()){for(int i=1;i<=n;i++) cur[i]=head[i];flow += DFS(s,inf);}return flow;} }DC;int main() {int T; scanf("%d",&T);for(int kase=1; kase<=T; ++kase){int n,m;scanf("%d%d",&n,&m);DC.init(n,1,n);while(m--){int u,v,w;scanf("%d%d%d",&u,&v,&w);DC.AddEdge(u,v,w);}printf("Case %d: %d\n",kase,DC.Maxflow());}return 0; }

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轉載于:https://www.cnblogs.com/lalalatianlalu/p/9033427.html

超強干貨來襲 云風專訪：近40年碼齡，通宵達旦的技術人生

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