import sys input=sys.stdin.readline # 最小費用流 from heapq import heappush, heappop class MinCostFlow: INF = 10**18 def __init__(self, N): self.N = N self.G = [[] for i in range(N)] def add_edge(self, fr, to, cap, cost): forward = [to, cap, cost, None] backward = forward[3] = [fr, 0, -cost, forward] self.G[fr].append(forward) self.G[to].append(backward) def flow(self, s, t, f): N = self.N; G = self.G INF = MinCostFlow.INF res = 0 H = [0]*N prv_v = [0]*N prv_e = [None]*N d0 = [INF]*N dist = [INF]*N while f: dist[:] = d0 dist[s] = 0 que = [(0, s)] while que: c, v = heappop(que) if dist[v] < c: continue r0 = dist[v] + H[v] for e in G[v]: w, cap, cost, _ = e if cap > 0 and r0 + cost - H[w] < dist[w]: dist[w] = r = r0 + cost - H[w] prv_v[w] = v; prv_e[w] = e heappush(que, (r, w)) if dist[t] == INF: return res return None for i in range(N): H[i] += dist[i] d = f; v = t while v != s: d = min(d, prv_e[v][1]) v = prv_v[v] f -= d res += d * H[t] v = t while v != s: e = prv_e[v] e[1] -= d e[3][1] += d v = prv_v[v] return res def main1(n,s,v): mcf=MinCostFlow(2*n+2) # 2*n->2*n+1 for i in range(n): mcf.add_edge(2*i,2*i+1,1,-v[i]) if s[i]=='y': mcf.add_edge(2*n,2*i,1,0) elif s[i]=='i': mcf.add_edge(2*i+1,2*n+1,1,0) for j in range(i): # j