二次联通门 : LibreOJ #102. 最小费用流
/* LibreOJ #102. 最小费用流 Spfa跑花费 记录路径 倒推回去 */ #include <cstring> #include <cstdio> #include <queue> #define Max 10000 void read (int &now) { now = 0; register char word = getchar (); while (word > ‘9‘ || word < ‘0‘) word = getchar (); while (word >= ‘0‘ && word <= ‘9‘) { now = now * 10 + word - ‘0‘; word = getchar (); } } inline int min (int a, int b) { return a < b ? a : b; } class Cost_Flow_Type { private : int __to[Max * 70]; int __next[Max * 70]; int __flow[Max * 70], __cost[Max * 70]; int edge_list[Max]; int Edge_Count; int dis[Max], can_flow[Max]; bool visit[Max]; int pre[Max]; public : Cost_Flow_Type () { Edge_Count = 1; } inline void Insert_edge (int from, int to, int flow, int cost) { Edge_Count ++; __to[Edge_Count] = to; __next[Edge_Count] = edge_list[from]; edge_list[from] = Edge_Count; __flow[Edge_Count] = flow; __cost[Edge_Count] = cost; Edge_Count ++; __to[Edge_Count] = from; __next[Edge_Count] = edge_list[to]; edge_list[to] = Edge_Count; __flow[Edge_Count] = 0; __cost[Edge_Count] = -cost; } bool Spfa (int Start, int End) { memset (dis, 0x3f, sizeof dis); memset (visit, false, sizeof visit); std :: queue <int> Queue; register int now; visit[Start] = true; can_flow[Start] = dis[0]; pre[Start] = 0; for (Queue.push (Start), dis[Start] = 0; !Queue.empty (); Queue.pop ()) { now = Queue.front (); visit[now] = false; for (int i = edge_list[now]; i; i = __next[i]) if (__flow[i] && dis[__to[i]] > dis[now] + __cost[i]) { dis[__to[i]] = dis[now] + __cost[i]; pre[__to[i]] = i; can_flow[__to[i]] = min (can_flow[now], __flow[i]); if (!visit[__to[i]]) { Queue.push (__to[i]); visit[__to[i]] = true; } } } return dis[End] < dis[0]; } void Get_Cost_Flow (int Start, int End) { int res = 0; int Cost_ = 0; for (int x; Spfa (Start, End); ) { x = can_flow[End]; for (int i = End; i != Start; i = __to[pre[i] ^ 1]) { __flow[pre[i]] -= x; __flow[pre[i] ^ 1] += x; } res += x; Cost_ += dis[End] * x; } printf ("%d %d", res, Cost_); } }; int N, M; Cost_Flow_Type Make; int main (int argc, char *argv[]) { int x, y, z, Flandre; for (read (N), read (M); M --; ) { read (x); read (y); read (z); read (Flandre); Make.Insert_edge (x, y, z, Flandre); } Make.Get_Cost_Flow (1, N); return 0; }
时间: 2024-08-10 02:03:16