結果

問題 No.20 砂漠のオアシス
ユーザー magurogumamaguroguma
提出日時 2020-01-04 22:35:53
言語 Go
(1.22.1)
結果
AC  
実行時間 45 ms / 5,000 ms
コード長 9,312 bytes
コンパイル時間 10,501 ms
コンパイル使用メモリ 219,976 KB
実行使用メモリ 10,112 KB
最終ジャッジ日時 2024-05-02 08:55:01
合計ジャッジ時間 11,423 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
6,816 KB
testcase_01 AC 2 ms
5,248 KB
testcase_02 AC 1 ms
6,816 KB
testcase_03 AC 3 ms
5,376 KB
testcase_04 AC 3 ms
5,376 KB
testcase_05 AC 29 ms
8,576 KB
testcase_06 AC 45 ms
10,112 KB
testcase_07 AC 43 ms
10,112 KB
testcase_08 AC 31 ms
8,576 KB
testcase_09 AC 43 ms
10,112 KB
testcase_10 AC 1 ms
5,376 KB
testcase_11 AC 2 ms
5,376 KB
testcase_12 AC 3 ms
5,376 KB
testcase_13 AC 4 ms
5,376 KB
testcase_14 AC 6 ms
5,376 KB
testcase_15 AC 5 ms
5,376 KB
testcase_16 AC 8 ms
5,376 KB
testcase_17 AC 7 ms
5,632 KB
testcase_18 AC 8 ms
5,376 KB
testcase_19 AC 9 ms
5,376 KB
testcase_20 AC 2 ms
5,376 KB
権限があれば一括ダウンロードができます

ソースコード

diff #

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?
*/

/*******************************************************************/
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