Uvalive 7264 Kejin Game (min cut)

Title Address: Https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem &problem=5276

Idea: Minimum cut. Split each point into I and I ', set a source point and a sink point.

1. For Edge I--->j, the edge i '--->j, the capacity is the cost of the corresponding side.

2. The source point to I edge, the capacity to meet the conditions after the purchase of I cost.

3. For I and I ' edge, the capacity is the cost of direct purchase I.

4. For the target point to the meeting point edge, the capacity is INF.

Because each cut in the diagram is a scheme to acquire a target skill, the minimum cut is required.

#include <cstdio> #include <queue> #include <vector> #include <cstring> #include <algorithm > #define Debuusing namespace std;const int maxn = 1010;const int INF = 0x3f3f3f3f;struct edge{int from, to, Cap, FL    ow    Edge (int a,int b,int c,int D): From (a), to (b), Cap (c), flow (d) {}};int n,m,goal;struct dinic{int n, m, S, t;    Vector<edge> edges;    Vector<int> G[MAXN];    BOOL VIS[MAXN];    int D[MAXN];    int CUR[MAXN];        void init (int n) {this->n=n;        for (int i = 0; I <= N; i++) g[i].clear ();    Edges.clear ();        } void Addedge (int from, int to, int cap) {Edges.push_back (Edge (from,to,cap,0));        Edges.push_back (Edge (to,from,0,0));        int m = Edges.size ();        G[from].push_back (m-2);    G[to].push_back (m-1);        } bool BFS () {memset (Vis, 0, sizeof (VIS));        Queue<int> Q;        Q.push (s);        Vis[s] = 1;        D[s] = 0; while (! Q.empty ()) {int X = Q.front ();            Q.pop ();                for (int i = 0; i < g[x].size (); i++) {edge& e = edges[g[x][i]];                    if (!vis[e.to] && e.cap > E.flow) {vis[e.to] = 1;                    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;            for (int& i = cur[x]; i < g[x].size (); i++) {edge& e = edges[g[x][i]];                if (d[x] + 1 = = D[e.to] && (f = DFS (e.to, Min (A, e.cap-e.flow))) > 0) {e.flow + = f;                Edges[g[x][i]^1].flow-= f;                Flow + + F;                A-= f;            if (a = = 0) break;    }} return flow;        } int Maxflow (int s, int t) {this->s = s;        This->t = t;      int flow = 0;  while (BFS ()) {memset (cur, 0, sizeof (cur));        Flow + = DFS (s, INF);    } return flow;    }};D inic G;int main () {#ifdef debug Freopen ("In.in", "R", stdin), #endif//debug int t;    scanf ("%d", &t);        while (t--) {scanf ("%d%d%d", &n,&m,&goal);        G.init (2*n+1);            for (int i=0; i<m; i++) {int x,y,c;            scanf ("%d%d%d", &x,&y,&c);        G.addedge (X+N,Y,C);            } for (int i=1; i<=n; i++) {int x;            scanf ("%d", &x);        G.addedge (0,I,X);            } for (int i=1; i<=n; i++) {int x;            scanf ("%d", &x);        G.addedge (I,I+N,X);        } g.addedge (Goal,2*n+1,inf);        int Ans=g.maxflow (0,2*n+1);    printf ("%d\n", ans); } return 0;}

Uvalive 7264 Kejin Game (min cut)