rename directory

11_largest_product_in_grid/main.go

@@ -0,0 +1,187 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	fi, err := os.Open("./digits.txt")
+	if err != nil {
+		panic(err)
+	}
+	defer fi.Close()
+
+	br := bufio.NewReader(fi)
+	var input [][]int
+	for {
+		a, _, e := br.ReadLine()
+		if e == io.EOF {
+			break
+		}
+		got := strings.Split(string(a), " ")
+		var line []int
+		for _, v := range got {
+			n, err := strconv.Atoi(v)
+			if err != nil {
+				panic(err)
+			}
+			line = append(line, n)
+		}
+		input = append(input, line)
+	}
+	fmt.Println("input=", input)
+
+	d4 := GetDown4(input)
+	fmt.Println(d4)
+
+	var product *Result
+	for y := 0; y < len(input); y++ {
+		for x := 0; x < len(input); x++ {
+			p1 := NewResult()
+			p2 := NewResult()
+			p3 := NewResult()
+			p4 := NewResult()
+			for i := 0; i < 4; i++ {
+				p1.Product *= GetAdjacent(input, y, x+i)
+				p1.Line = append(p1.Line, GetAdjacent(input, y, x+i))
+				p2.Product *= GetAdjacent(input, y+i, x)
+				p2.Line = append(p2.Line, GetAdjacent(input, y+i, x))
+				p3.Product *= GetAdjacent(input, y+i, x+i)
+				p3.Line = append(p3.Line, GetAdjacent(input, y+i, x+i))
+				p4.Product *= GetAdjacent(input, y+i, x-i)
+				p4.Line = append(p4.Line, GetAdjacent(input, y+i, x-i))
+			}
+			product = Max(p1, p2, p3, p4, product)
+		}
+	}
+
+	fmt.Println("product is", product)
+}
+
+type Result struct {
+	Product int
+	Line    []int
+}
+
+func NewResult() *Result {
+	return &Result{
+		Product: 1,
+	}
+}
+
+func (r *Result) String() string {
+	return fmt.Sprintln("product is", r.Product, "line:", r.Line)
+}
+
+func Max(n, n2, n3, n4, n5 *Result) *Result {
+	max := NewResult()
+	if n.Product > max.Product {
+		max = n
+	}
+	if n2.Product > max.Product {
+		max = n2
+	}
+	if n3.Product > max.Product {
+		max = n3
+	}
+	if n4.Product > max.Product {
+		max = n4
+	}
+	if n5 != nil && n5.Product > max.Product {
+		max = n5
+	}
+	return max
+}
+
+func GetAdjacent(input [][]int, x, y int) int {
+	if 0 <= y && y < len(input) && 0 <= x && x < len(input[y]) {
+		return input[y][x]
+	}
+	return 0
+}
+
+func GetRight4(input [][]int) [][]int {
+	var ret [][]int
+	for _, line := range input {
+		l := len(line)
+		if l < 4 {
+			continue
+		} else if l == 4 {
+			ret = append(ret, line)
+		} else {
+			for x := 0; x+4 <= l; x++ {
+				ret = append(ret, line[x:x+4])
+			}
+		}
+	}
+	return ret
+}
+
+func GetDown4(input [][]int) [][]int {
+	length := len(input)
+	if length < 4 {
+		return nil
+	}
+	maxL := 0
+	for _, line := range input {
+		if len(line) > maxL {
+			maxL = len(line)
+		}
+	}
+	var ret [][]int
+	for c := 0; c < maxL; c++ {
+		for l := 0; l <= length-4; l++ {
+			var one []int
+			for d := 0; d < 4; d++ {
+				if len(input[l+d]) > c {
+					one = append(one, input[l+d][c])
+				}
+			}
+			if len(one) == 4 {
+				ret = append(ret, one)
+			}
+		}
+	}
+	return ret
+}
+
+func GetDiagonal4(input [][]int) [][]int {
+	l := len(input)
+	if l < 4 {
+		return nil
+	}
+	maxL := 0
+	for _, line := range input {
+		if len(line) > maxL {
+			maxL = len(line)
+		}
+	}
+	if maxL < 4 {
+		return nil
+	}
+	var ret [][]int
+	for x := 0; x < maxL; x++ {
+		for y := 0; y < l; y++ {
+			if l < y+4 {
+				break
+			}
+			var l []int
+			for d := 0; d < 4; d++ {
+				line := input[d+y]
+				if len(line) <= d+x {
+					break
+				}
+				l = append(l, line[x+d])
+			}
+			if len(l) == 4 {
+				ret = append(ret, l)
+			}
+		}
+	}
+	return ret
+}