package main import ( "bufio" "fmt" "os" ) const INF int = 1e18 func removeYuki(s string, scores []int) int { n := len(s) A := func(i int) int { return i } B := func(i int) int { return n + 1 + i } C := func(i int) int { return 2*(n+1) + i } D := func(i int) int { return 3*(n+1) + i } E := func(i int) int { return 4*(n+1) + i } mcmf := NewMinCostFlow(5*n+5, A(0), E(n)) for i := 0; i < n; i++ { mcmf.AddEdge(A(i), A(i+1), n, 0) mcmf.AddEdge(B(i), B(i+1), n, 0) mcmf.AddEdge(C(i), C(i+1), n, 0) mcmf.AddEdge(D(i), D(i+1), n, 0) mcmf.AddEdge(E(i), E(i+1), n, 0) } for i := 0; i < n; i++ { if s[i] == 'y' { mcmf.AddEdge(A(i), B(i+1), 1, -scores[i]) } if s[i] == 'u' { mcmf.AddEdge(B(i), C(i+1), 1, -scores[i]) } if s[i] == 'k' { mcmf.AddEdge(C(i), D(i+1), 1, -scores[i]) } if s[i] == 'i' { mcmf.AddEdge(D(i), E(i+1), 1, -scores[i]) } } _, maxCost := mcmf.Work() return -maxCost } type MinCostFlow struct { AddEdge func(from, to, cap, cost int) Work func() (maxFlow int, minCost int) } func NewMinCostFlow(n, start, end int) *MinCostFlow { type neighbor struct { to int rid int // rid 为反向边在邻接表中的下标 cap int // 边的残量 cost int eid int // -1表示是反向边 } graph := make([][]neighbor, n) ei := 0 addEdge := func(from, to, cap, cost, eid int) { graph[from] = append(graph[from], neighbor{to, len(graph[to]), cap, cost, eid}) graph[to] = append(graph[to], neighbor{from, len(graph[from]) - 1, 0, -cost, -1}) } dist := make([]int, len(graph)) type vi struct{ v, i int } pre := make([]vi, len(graph)) spfa := func() bool { for i := range dist { dist[i] = INF } dist[start] = 0 inQueue := make([]bool, len(graph)) inQueue[start] = true queue := []int{start} for len(queue) > 0 { cur := queue[0] queue = queue[1:] inQueue[cur] = false for i, edge := range graph[cur] { if edge.cap == 0 { continue } next := edge.to if cand := dist[cur] + int(edge.cost); cand < dist[next] { dist[next] = cand pre[next] = vi{cur, i} if !inQueue[next] { queue = append(queue, next) inQueue[next] = true } } } } return dist[end] < INF } ek := func() (maxFlow int, minCost int) { for spfa() { // 沿 st-end 的最短路尽量增广 flow := INF for cur := end; cur != start; { p := pre[cur] if c := graph[p.v][p.i].cap; c < flow { flow = c } cur = p.v } for cur := end; cur != start; { p := pre[cur] edge := &graph[p.v][p.i] edge.cap -= flow graph[cur][edge.rid].cap += flow cur = p.v } maxFlow += flow minCost += dist[end] * flow } return } AddEdge := func(from, to, cap, cost int) { addEdge(from, to, cap, cost, ei) ei++ } return &MinCostFlow{ AddEdge: AddEdge, Work: ek, } } func main() { in := bufio.NewReader(os.Stdin) out := bufio.NewWriter(os.Stdout) defer out.Flush() var n int fmt.Fscan(in, &n) var s string fmt.Fscan(in, &s) scores := make([]int, n) for i := 0; i < n; i++ { fmt.Fscan(in, &scores[i]) } fmt.Fprintln(out, removeYuki(s, scores)) }