package main import ( "bufio" "container/heap" "errors" "fmt" "io" "math" "os" "strconv" ) /*********** I/O ***********/ var ( // ReadString returns a WORD string. ReadString func() string stdout *bufio.Writer ) func init() { ReadString = newReadString(os.Stdin) stdout = bufio.NewWriter(os.Stdout) } func newReadString(ior io.Reader) func() string { r := bufio.NewScanner(ior) // r.Buffer(make([]byte, 1024), int(1e+11)) // for AtCoder r.Buffer(make([]byte, 1024), int(1e+9)) // for Codeforces // Split sets the split function for the Scanner. The default split function is ScanLines. // Split panics if it is called after scanning has started. r.Split(bufio.ScanWords) return func() string { if !r.Scan() { panic("Scan failed") } return r.Text() } } // ReadInt returns an integer. func ReadInt() int { return int(readInt64()) } func ReadInt2() (int, int) { return int(readInt64()), int(readInt64()) } func ReadInt3() (int, int, int) { return int(readInt64()), int(readInt64()), int(readInt64()) } func ReadInt4() (int, int, int, int) { return int(readInt64()), int(readInt64()), int(readInt64()), int(readInt64()) } // ReadInt64 returns as integer as int64. func ReadInt64() int64 { return readInt64() } func ReadInt64_2() (int64, int64) { return readInt64(), readInt64() } func ReadInt64_3() (int64, int64, int64) { return readInt64(), readInt64(), readInt64() } func ReadInt64_4() (int64, int64, int64, int64) { return readInt64(), readInt64(), readInt64(), readInt64() } func readInt64() int64 { i, err := strconv.ParseInt(ReadString(), 0, 64) if err != nil { panic(err.Error()) } return i } // ReadIntSlice returns an integer slice that has n integers. func ReadIntSlice(n int) []int { b := make([]int, n) for i := 0; i < n; i++ { b[i] = ReadInt() } return b } // ReadInt64Slice returns as int64 slice that has n integers. func ReadInt64Slice(n int) []int64 { b := make([]int64, n) for i := 0; i < n; i++ { b[i] = ReadInt64() } return b } // ReadFloat64 returns an float64. func ReadFloat64() float64 { return float64(readFloat64()) } func readFloat64() float64 { f, err := strconv.ParseFloat(ReadString(), 64) if err != nil { panic(err.Error()) } return f } // ReadFloatSlice returns an float64 slice that has n float64. func ReadFloat64Slice(n int) []float64 { b := make([]float64, n) for i := 0; i < n; i++ { b[i] = ReadFloat64() } return b } // ReadRuneSlice returns a rune slice. func ReadRuneSlice() []rune { return []rune(ReadString()) } /*********** Debugging ***********/ // ZeroPaddingRuneSlice returns binary expressions of integer n with zero padding. // For debugging use. func ZeroPaddingRuneSlice(n, digitsNum int) []rune { sn := fmt.Sprintf("%b", n) residualLength := digitsNum - len(sn) if residualLength <= 0 { return []rune(sn) } zeros := make([]rune, residualLength) for i := 0; i < len(zeros); i++ { zeros[i] = '0' } res := []rune{} res = append(res, zeros...) res = append(res, []rune(sn)...) return res } // Strtoi is a wrapper of strconv.Atoi(). // If strconv.Atoi() returns an error, Strtoi calls panic. func Strtoi(s string) int { if i, err := strconv.Atoi(s); err != nil { panic(errors.New("[argument error]: Strtoi only accepts integer string")) } else { return i } } // PrintIntsLine returns integers string delimited by a space. func PrintIntsLine(A ...int) string { res := []rune{} for i := 0; i < len(A); i++ { str := strconv.Itoa(A[i]) res = append(res, []rune(str)...) if i != len(A)-1 { res = append(res, ' ') } } return string(res) } // PrintIntsLine returns integers string delimited by a space. func PrintInts64Line(A ...int64) string { res := []rune{} for i := 0; i < len(A); i++ { str := strconv.FormatInt(A[i], 10) // 64bit int version res = append(res, []rune(str)...) if i != len(A)-1 { res = append(res, ' ') } } return string(res) } // PrintDebug is wrapper of fmt.Fprintf(os.Stderr, format, a...) func PrintDebug(format string, a ...interface{}) { fmt.Fprintf(os.Stderr, format, a...) } /********** FAU standard libraries **********/ //fmt.Sprintf("%b\n", 255) // binary expression /********** I/O usage **********/ //str := ReadString() //i := ReadInt() //X := ReadIntSlice(n) //S := ReadRuneSlice() //a := ReadFloat64() //A := ReadFloat64Slice(n) //str := ZeroPaddingRuneSlice(num, 32) //str := PrintIntsLine(X...) /* ASCII code ASCII 10進数 ASCII 10進数 ASCII 10進数 ! 33 " 34 # 35 $ 36 % 37 & 38 ' 39 ( 40 ) 41 * 42 + 43 , 44 - 45 . 46 / 47 0 48 1 49 2 50 3 51 4 52 5 53 6 54 7 55 8 56 9 57 : 58 ; 59 < 60 = 61 > 62 ? 63 @ 64 A 65 B 66 C 67 D 68 E 69 F 70 G 71 H 72 I 73 J 74 K 75 L 76 M 77 N 78 O 79 P 80 Q 81 R 82 S 83 T 84 U 85 V 86 W 87 X 88 Y 89 Z 90 [ 91 \ 92 ] 93 ^ 94 _ 95 ` 96 a 97 b 98 c 99 d 100 e 101 f 102 g 103 h 104 i 105 j 106 k 107 l 108 m 109 n 110 o 111 p 112 q 113 r 114 s 115 t 116 u 117 v 118 w 119 x 120 y 121 z 122 { 123 | 124 } 125 ~ 126 127 */ /*******************************************************************/ const ( // General purpose MOD = 1000000000 + 7 ALPHABET_NUM = 26 INF_INT64 = math.MaxInt64 INF_BIT60 = 1 << 60 INF_INT32 = math.MaxInt32 INF_BIT30 = 1 << 30 NIL = -1 // for dijkstra, prim, and so on WHITE = 0 GRAY = 1 BLACK = 2 ) var n, v int var ox, oy int var L [][]int func main() { n, v, ox, oy = ReadInt4() for i := 0; i < n; i++ { row := ReadIntSlice(n) L = append(L, row) } for i := 0; i < n; i++ { for j := 0; j < n; j++ { cid := i*n + j // LRUDの順で辺の有無をチェック if j-1 >= 0 { nid := i*n + (j - 1) G[cid] = append(G[cid], Edge{to: nid, cost: L[i][j-1]}) } if j+1 < n { nid := i*n + (j + 1) G[cid] = append(G[cid], Edge{to: nid, cost: L[i][j+1]}) } if i+1 < n { nid := (i+1)*n + j G[cid] = append(G[cid], Edge{to: nid, cost: L[i+1][j]}) } if i-1 >= 0 { nid := (i-1)*n + j G[cid] = append(G[cid], Edge{to: nid, cost: L[i-1][j]}) } } } // オアシスなしでダイクストラ dp := dijkstra(0) PrintDebug("%v\n", dp[:n*n]) if dp[n*n-1] < v { fmt.Println("YES") return } // オアシスがある場合は、そこを経由してダイクストラ if ox == 0 && oy == 0 { fmt.Println("NO") return } ox-- oy-- vv := v - dp[n*oy+ox] if vv <= 0 { fmt.Println("NO") return } vv *= 2 dp = dijkstra(n*oy + ox) if dp[n*n-1] < vv { fmt.Println("YES") return } fmt.Println("NO") } const NUM = 40000 + 5 func dijkstra(sid int) []int { dp, colors, parents := make([]int, NUM), make([]int, NUM), make([]int, NUM) for i := 0; i < NUM; i++ { dp[i], colors[i], parents[i] = INF_BIT30, WHITE, NIL } dp[sid], colors[sid], parents[sid] = 0, GRAY, NIL temp := make(VertexPQ, 0, 100000+1) pq := &temp heap.Init(pq) heap.Push(pq, &Vertex{pri: 0, id: sid}) for pq.Len() > 0 { cv := heap.Pop(pq).(*Vertex) colors[cv.id] = BLACK if dp[cv.id] < cv.pri { continue } for _, e := range G[cv.id] { if colors[e.to] == BLACK { continue } if dp[e.to] > dp[cv.id]+e.cost { dp[e.to] = dp[cv.id] + e.cost colors[e.to] = GRAY parents[e.to] = cv.id heap.Push(pq, &Vertex{pri: dp[e.to], id: e.to}) } } } return dp } var G [NUM][]Edge type Edge struct { to, cost int } type Vertex struct { pri int id int } type VertexPQ []*Vertex func (pq VertexPQ) Len() int { return len(pq) } func (pq VertexPQ) Less(i, j int) bool { return pq[i].pri < pq[j].pri } // <: ASC, >: DESC func (pq VertexPQ) Swap(i, j int) { pq[i], pq[j] = pq[j], pq[i] } func (pq *VertexPQ) Push(x interface{}) { item := x.(*Vertex) *pq = append(*pq, item) } func (pq *VertexPQ) Pop() interface{} { old := *pq n := len(old) item := old[n-1] *pq = old[0 : n-1] return item } // how to use // temp := make(VertexPQ, 0, 100000+1) // pq := &temp // heap.Init(pq) // heap.Push(pq, &Vertex{pri: intValue}) // popped := heap.Pop(pq).(*Vertex) /* - まずは全探索を検討しましょう - MODは最後にとりましたか？ - ループを抜けた後も処理が必要じゃありませんか？ - 和・積・あまりを求められたらint64が必要ではありませんか？ - いきなりオーバーフローはしていませんか？ - MOD取る系はint64必須ですよ？ */ /*******************************************************************/