import sys input = lambda : sys.stdin.readline().rstrip() write = lambda x: sys.stdout.write(x+"\n") debug = lambda x: sys.stderr.write(x+"\n") writef = lambda x: print("{:.12f}".format(x)) from typing import NamedTuple, Optional, List, cast class MFGraph: class Edge(NamedTuple): src: int dst: int cap: int flow: int class _Edge: def __init__(self, dst: int, cap: int) -> None: self.dst = dst self.cap = cap self.rev: Optional[MFGraph._Edge] = None def __init__(self, n: int) -> None: self._n = n self._g: List[List[MFGraph._Edge]] = [[] for _ in range(n)] self._edges: List[MFGraph._Edge] = [] def add_edge(self, src: int, dst: int, capacity: int) -> int: assert 0 <= src < self._n assert 0 <= dst < self._n m = len(self._edges) e = MFGraph._Edge(dst, capacity) re = MFGraph._Edge(src, 0) e.rev = re re.rev = e self._g[src].append(e) self._g[dst].append(re) self._edges.append(e) return m def get_edge(self, i: int) -> Edge: assert 0 <= i < len(self._edges) e = self._edges[i] re = cast(MFGraph._Edge, e.rev) return MFGraph.Edge( re.dst, e.dst, e.cap + re.cap, re.cap ) def edges(self) -> List[Edge]: return [self.get_edge(i) for i in range(len(self._edges))] def change_edge(self, i: int, new_cap: int, new_flow: int) -> None: assert 0 <= i < len(self._edges) assert 0 <= new_flow <= new_cap e = self._edges[i] e.cap = new_cap - new_flow assert e.rev is not None e.rev.cap = new_flow def flow(self, s: int, t: int, flow_limit: Optional[int] = None) -> int: assert 0 <= s < self._n assert 0 <= t < self._n assert s != t if flow_limit is None: flow_limit = cast(int, sum(e.cap for e in self._g[s])) current_edge = [0] * self._n level = [0] * self._n def fill(arr: List[int], value: int) -> None: for i in range(len(arr)): arr[i] = value def bfs() -> bool: fill(level, self._n) queue = [] q_front = 0 queue.append(s) level[s] = 0 while q_front < len(queue): v = queue[q_front] q_front += 1 next_level = level[v] + 1 for e in self._g[v]: if e.cap == 0 or level[e.dst] <= next_level: continue level[e.dst] = next_level if e.dst == t: return True queue.append(e.dst) return False def dfs(lim: int) -> int: stack = [] edge_stack: List[MFGraph._Edge] = [] stack.append(t) while stack: v = stack[-1] if v == s: flow = min(lim, min(e.cap for e in edge_stack)) for e in edge_stack: e.cap -= flow assert e.rev is not None e.rev.cap += flow return flow next_level = level[v] - 1 while current_edge[v] < len(self._g[v]): e = self._g[v][current_edge[v]] re = cast(MFGraph._Edge, e.rev) if level[e.dst] != next_level or re.cap == 0: current_edge[v] += 1 continue stack.append(e.dst) edge_stack.append(re) break else: stack.pop() if edge_stack: edge_stack.pop() level[v] = self._n return 0 flow = 0 while flow < flow_limit: if not bfs(): break fill(current_edge, 0) while flow < flow_limit: f = dfs(flow_limit - flow) flow += f if f == 0: break return flow def min_cut(self, s: int) -> List[bool]: visited = [False] * self._n stack = [s] visited[s] = True while stack: v = stack.pop() for e in self._g[v]: if e.cap > 0 and not visited[e.dst]: visited[e.dst] = True stack.append(e.dst) return visited ### 二部グラフマッチングの例 def bimatch(ns): n = len(ns) m = n # DiGraphにしないとMinフローと最大マッチングが一致しない g = MFGraph(n+m+2) s = n+m t = n+m+1 for u in range(n): g.add_edge(s, u, capacity=1) for v in ns[u]: g.add_edge(u, v+n, capacity=1) for v in range(m): g.add_edge(n+v, t, capacity=1) val = g.flow(s, t, flow_limit=n) return val, g.edges() def bimatch_grid(r,c,s): """グリッド上の二部グラフの例 (隣接するsの値が異なるところに枝を貼る) """ g = MFGraph(r*c+2) S = r*c T = r*c+1 for i in range(r): for j in range(c): if not need[i][j]: continue nn = node(i,j) if (i+j)%2==0: g.add_edge(S, nn, capacity=1) f = 0 else: g.add_edge(nn, T, capacity=1) f = 1 tmp = [] if i>0 and s[i-1][j]!=s[i][j]: tmp.append(node(i-1,j)) if i+10 and s[i][j-1]!=s[i][j]: tmp.append(node(i,j-1)) if j+1