pwc248 solution in go

2 files changed, 204 insertions, 0 deletions

diff --git a/challenge-248/pokgopun/go/ch-1.go b/challenge-248/pokgopun/go/ch-1.go
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+++ b/challenge-248/pokgopun/go/ch-1.go
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+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-248/
+/*#
+
+Task 1: Shortest Distance
+
+Submitted by: [58]Mohammad S Anwar
+     __________________________________________________________________
+
+   You are given a string and a character in the given string.
+
+   Write a script to return an array of integers of size same as length of
+   the given string such that:
+distance[i] is the distance from index i to the closest occurence of
+the given character in the given string.
+
+The distance between two indices i and j is abs(i - j).
+
+Example 1
+
+Input: $str = "loveleetcode", $char = "e"
+Output: (3,2,1,0,1,0,0,1,2,2,1,0)
+
+The character 'e' appears at indices 3, 5, 6, and 11 (0-indexed).
+The closest occurrence of 'e' for index 0 is at index 3, so the distance is abs(
+0 - 3) = 3.
+The closest occurrence of 'e' for index 1 is at index 3, so the distance is abs(
+1 - 3) = 2.
+For index 4, there is a tie between the 'e' at index 3 and the 'e' at index 5,
+but the distance is still the same: abs(4 - 3) == abs(4 - 5) = 1.
+The closest occurrence of 'e' for index 8 is at index 6, so the distance is abs(
+8 - 6) = 2.
+
+Example 2
+
+Input: $str = "aaab", $char = "b"
+Output: (3,2,1,0)
+
+Task 2: Submatrix Sum
+#*/
+//# solution by pokgopun@gmail.com
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+type word string
+
+func (w word) indexes(r rune) []int {
+	idxs := []int{}
+	for i, v := range w {
+		if v == r {
+			idxs = append(idxs, i)
+		}
+	}
+	return idxs
+}
+
+func (w word) shortestDistance(r rune) []int {
+	pos := w.indexes(r)
+	if len(pos) == 0 {
+		return []int{}
+	}
+	l := len(w)
+	s := make([]int, l)
+	var d, p int
+	for l > 0 {
+		l--
+		s[l] = max(l, pos[0]) - min(l, pos[0])
+		for _, p = range pos[1:] {
+			d = max(l, p) - min(l, p)
+			if d < s[l] {
+				s[l] = d
+			}
+		}
+	}
+	return s
+}
+
+func main() {
+	for _, data := range []struct {
+		wrd    word
+		lttr   rune
+		dstnce []int
+	}{
+		{"loveleetcode", 'e', []int{3, 2, 1, 0, 1, 0, 0, 1, 2, 2, 1, 0}},
+		{"aaab", 'b', []int{3, 2, 1, 0}},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(data.wrd.shortestDistance(data.lttr), data.dstnce)) // output nothing if ok, otherwise show the difference
+	}
+}
diff --git a/challenge-248/pokgopun/go/ch-2.go b/challenge-248/pokgopun/go/ch-2.go
new file mode 100644
index 0000000000..f626d45750
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+++ b/challenge-248/pokgopun/go/ch-2.go
@@ -0,0 +1,109 @@
+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-248/
+/*#
+
+Task 2: Submatrix Sum
+
+Submitted by: [59]Jorg Sommrey
+     __________________________________________________________________
+
+   You are given a NxM matrix A of integers.
+
+   Write a script to construct a (N-1)x(M-1) matrix B having elements that
+   are the sum over the 2x2 submatrices of A,
+b[i,k] = a[i,k] + a[i,k+1] + a[i+1,k] + a[i+1,k+1]
+
+Example 1
+
+Input: $a = [
+              [1,  2,  3,  4],
+              [5,  6,  7,  8],
+              [9, 10, 11, 12]
+            ]
+
+Output: $b = [
+               [14, 18, 22],
+               [30, 34, 38]
+             ]
+
+Example 2
+
+Input: $a = [
+              [1, 0, 0, 0],
+              [0, 1, 0, 0],
+              [0, 0, 1, 0],
+              [0, 0, 0, 1]
+            ]
+
+Output: $b = [
+               [2, 1, 0],
+               [1, 2, 1],
+               [0, 1, 2]
+             ]
+     __________________________________________________________________
+
+   Last date to submit the solution 23:59 (UK Time) Sunday 24th December
+   2023.
+     __________________________________________________________________
+
+SO WHAT DO YOU THINK ?
+#*/
+//# solution by pokgopun@gmail.com
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+type cols []int
+
+type rows []cols
+
+func (rws rows) sub() rows {
+	d := len(rws)
+	l := len(rws[0])
+	s := make(rows, d-1)
+	for r := 0; r < d-1; r++ {
+		s[r] = make(cols, l-1)
+		for c := 0; c < l-1; c++ {
+			s[r][c] = rws[r][c] + rws[r][c+1] + rws[r+1][c] + rws[r+1][c+1]
+		}
+	}
+	return s
+}
+
+func main() {
+	for _, data := range []struct {
+		input, output rows
+	}{
+		{
+			rows{
+				cols{1, 2, 3, 4},
+				cols{5, 6, 7, 8},
+				cols{9, 10, 11, 12},
+			},
+			rows{
+				cols{14, 18, 22},
+				cols{30, 34, 38},
+			},
+		},
+		{
+			rows{
+				cols{1, 0, 0, 0},
+				cols{0, 1, 0, 0},
+				cols{0, 0, 1, 0},
+				cols{0, 0, 0, 1},
+			},
+			rows{
+				cols{2, 1, 0},
+				cols{1, 2, 1},
+				cols{0, 1, 2},
+			},
+		},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(data.output, data.input.sub())) // output nothing if ok, otherwise ouput difference
+	}
+}