pwc252 solution in go

2 files changed, 224 insertions, 0 deletions

diff --git a/challenge-252/pokgopun/go/ch-1.go b/challenge-252/pokgopun/go/ch-1.go
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+++ b/challenge-252/pokgopun/go/ch-1.go
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+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-252/
+/*#
+
+Task 1: Special Numbers
+
+Submitted by: [45]Mohammad S Anwar
+     __________________________________________________________________
+
+   You are given an array of integers, @ints.
+
+   Write a script to find the sum of the squares of all special elements
+   of the given array.
+An element $int[i] of @ints is called special if i divides n, i.e. n % i == 0.
+Where n is the length of the given array. Also the array is 1-indexed for the ta
+sk.
+
+Example 1
+
+Input: @ints = (1, 2, 3, 4)
+Output: 21
+
+There are exactly 3 special elements in the given array:
+$ints[1] since 1 divides 4,
+$ints[2] since 2 divides 4, and
+$ints[4] since 4 divides 4.
+
+Hence, the sum of the squares of all special elements of given array:
+1 * 1 + 2 * 2 + 4 * 4 = 21.
+
+Example 2
+
+Input: @ints = (2, 7, 1, 19, 18, 3)
+Output: 63
+
+There are exactly 4 special elements in the given array:
+$ints[1] since 1 divides 6,
+$ints[2] since 2 divides 6,
+$ints[3] since 3 divides 6, and
+$ints[6] since 6 divides 6.
+
+Hence, the sum of the squares of all special elements of given array:
+2 * 2 + 7 * 7 + 1 * 1 + 3 * 3 = 63
+
+Task 2: Unique Sum Zero
+#*/
+//# solution by pokgopun@gmail.com
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+type ints []int
+
+func (is ints) snum() int {
+	l := len(is)
+	r := 0
+	for i, v := range is {
+		if l%(i+1) == 0 {
+			r += v * v
+		}
+	}
+	return r
+}
+
+func main() {
+	for _, data := range []struct {
+		input  ints
+		output int
+	}{
+		{ints{1, 2, 3, 4}, 21},
+		{ints{2, 7, 1, 19, 18, 3}, 63},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(data.input.snum(), data.output)) // blank if ok, otherwise show the difference
+	}
+}
diff --git a/challenge-252/pokgopun/go/ch-2.go b/challenge-252/pokgopun/go/ch-2.go
new file mode 100644
index 0000000000..d8d9654546
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+++ b/challenge-252/pokgopun/go/ch-2.go
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+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-252/
+/*#
+
+Task 2: Unique Sum Zero
+
+Submitted by: [46]Mohammad S Anwar
+     __________________________________________________________________
+
+   You are given an integer, $n.
+
+   Write a script to find an array containing $n unique integers such that
+   they add up to zero.
+
+Example 1
+
+Input: $n = 5
+Output: (-7, -1, 1, 3, 4)
+
+Two other possible solutions could be as below:
+(-5, -1, 1, 2, 3) and (-3, -1, 2, -2, 4).
+
+Example 2
+
+Input: $n = 3
+Output: (-1, 0, 1)
+
+Example 3
+
+Input: $n = 1
+Output: (0)
+     __________________________________________________________________
+
+   Last date to submit the solution 23:59 (UK Time) Sunday 21st January
+   2024.
+     __________________________________________________________________
+
+SO WHAT DO YOU THINK ?
+#*/
+//# solution by pokgopun@gmail.com
+
+package main
+
+import (
+	"io"
+	"os"
+	"slices"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func isUsz(n int, s []int) bool {
+	slices.Sort(s)
+	l := 0
+	for i := 1; i < n; i++ {
+		l -= i
+	}
+	p := make([]int, n-l)
+	for i := 0; i < n-l; i++ {
+		p[i] = l + i
+	}
+	for v := range Combinations(p, uint(n)) {
+		sum := 0
+		for _, i := range v {
+			sum += i
+		}
+		if sum == 0 && cmp.Diff(v, s) == "" {
+			return true
+		}
+	}
+	return false
+}
+
+type ints []int
+
+func main() {
+	for _, data := range []struct {
+		n   int
+		arr ints
+		res bool
+	}{
+		{5, ints{-7, -1, 1, 3, 4}, true},
+		{5, ints{-5, -1, 1, 2, 3}, true},
+		{5, ints{-3, -1, 2, -2, 4}, true},
+		{3, ints{-1, 0, 1}, true},
+		{1, ints{0}, true},
+		{5, ints{-6, -1, 1, 3, 4}, false},
+		{5, ints{-5, 1, 1, 2, 3}, false},
+		{5, ints{-3, -1, 1, 2, 4}, false},
+		{3, ints{-2, 0, 1}, false},
+		{1, ints{1}, false},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(isUsz(data.n, data.arr), data.res)) // blank if ok, otherwise show the difference
+	}
+}
+
+// transcribed from https://docs.python.org/3/library/itertools.html#itertools.combinations
+func Combinations[E any](s []E, r uint) chan []E {
+	res := make(chan []E)
+	n := uint(len(s))
+	if r > n {
+		go func() {
+			res <- []E{}
+			close(res)
+		}()
+		return res
+	}
+	go func() {
+		res <- s[:r]
+		idx := make([]uint, r)
+		for i := range idx {
+			idx[i] = uint(i)
+		}
+		var i, j uint
+		for {
+			i = r
+			for {
+				i--
+				if idx[i] != i+n-r {
+					break
+				}
+				if i > 0 {
+					continue
+				}
+				close(res)
+				return
+			}
+			idx[i]++
+			j = i + 1
+			for j < r {
+				idx[j] = idx[j-1] + 1
+				j++
+			}
+			result := make([]E, r)
+			i = 0
+			for _, v := range idx {
+				result[i] = s[v]
+				i++
+			}
+			res <- result
+		}
+		close(res)
+	}()
+	return res
+}