[模板]洛谷P3381 最小费用最大流(dinic)
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#include<bits/stdc++.h> #define ll long long #define PB push_back #define endl '\n' #define INF 0x3f3f3f3f #define LINF 0x3f3f3f3f3f3f3f3f #define ull unsigned long long #define lson rt << 1, l, mid #define rson rt << 1 | 1, mid + 1, r #define lowbit(x) (x & (-x)) #define rep(i, a, b) for(int i = a ; i <= b ; ++ i) #define per(i, a, b) for(int i = b ; i >= a ; -- i) #define clr(a, b) memset(a, b, sizeof(a)) #define in insert #define random(x) (rand()%x) #define PII(x, y) make_pair(x, y) #define fi first #define se second #define pi acos(-1) using namespace std; const int maxn = 2e6 + 1000; const ll mod = 998244353; const int M = 50000 + 10; const int N = 5000 + 10; int n, m, s, t, cnt; int head[N], vis[N], inq[N], cur[N]; ll dis[N]; ll maxflow, cost; struct node{ int to, next; ll cost, flow; }edge[M<<1]; void add(int u, int v, int cost, int flow){ edge[cnt].to = v; edge[cnt].cost = cost; edge[cnt].flow = flow; edge[cnt].next = head[u]; head[u] = cnt ++; } bool spfa(){ rep(i, 1, n) dis[i] = 1e18, inq[i] = 0, cur[i] = head[i]; queue<int> que; dis[s] = 0; inq[s] = 1; que.push(s); while(!que.empty()){ int u = que.front(); que.pop(); inq[u] = 0; for(int i = head[u] ; ~ i ; i = edge[i].next){ int v = edge[i].to; if(dis[v] > dis[u] + edge[i].cost && edge[i].flow){ dis[v] = dis[u] + edge[i].cost; if(!inq[v]){ inq[v] = 1; que.push(v); } } } } return dis[t] == 1e18 ? 0 : 1; } ll dfs(int u, ll flow){ if(u == t){ vis[t] = 1; maxflow += flow; return flow; } ll used = 0; vis[u] = 1; for(int i = cur[u] ; ~ i ; i = edge[i].next){ int v = edge[i].to; cur[u] = i; if((v == t || !vis[v]) && edge[i].flow && dis[v] == dis[u] + edge[i].cost){ ll minflow = dfs(v, min(flow - used, edge[i].flow)); if(minflow){ cost += minflow * edge[i].cost; edge[i].flow -= minflow; edge[i^1].flow += minflow; used += minflow; } if(used == flow) break; } } return used; } void dinic(){ while(spfa()){ vis[t] = 1; while(vis[t]){ clr(vis, 0); dfs(s, 1e18); } } } signed main(){ ll u, v, w, z; int q; scanf("%d %d %d %d", &n, &m, &s, &t); clr(head, -1); clr(vis, 0); maxflow = cost = 0; //s = 1; t = n; cnt = 0; while(m --){ scanf("%lld %lld %lld %lld", &u, &v, &w, &z); add(u, v, z, w); add(v, u, -z, 0); } dinic(); cout << maxflow << ' ' << cost << endl; return 0; }