pwc346 solution in lua

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diff --git a/challenge-346/pokgopun/lua/ch-1.lua b/challenge-346/pokgopun/lua/ch-1.lua
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+--# https://theweeklychallenge.org/blog/perl-weekly-challenge-346/
+--[[
+
+Task 1: Longest Parenthesis
+
+Submitted by: [44]Mohammad Sajid Anwar
+     __________________________________________________________________
+
+   You are given a string containing only ( and ).
+
+   Write a script to find the length of the longest valid parenthesis.
+
+Example 1
+
+Input: $str = '(()())'
+Output: 6
+
+Valid Parenthesis: '(()())'
+
+Example 2
+
+Input: $str = ')()())'
+Output: 4
+
+Valid Parenthesis: '()()' at positions 1-4.
+
+Example 3
+
+Input: $str = '((()))()(((()'
+Output: 8
+
+Valid Parenthesis: '((()))()' at positions 0-7.
+
+Example 4
+
+Input: $str = '))))((()('
+Output: 2
+
+Valid Parenthesis: '()' at positions 6-7.
+
+Example 5
+
+Input: $str = '()(()'
+Output: 2
+
+Valid Parenthesis: '()' at positions 0-1 and 3-4.
+
+Task 2: Magic Expression
+--]]
+--# solution by pokgopun@gmail.com
+
+--@param string
+local function lp(str) --@return int
+	local p = {}
+	for i=1, #str do
+		p[i] = str:sub(i,i)
+	end
+	local c = 0
+	local mx = 0
+	for i=1, #str do
+		--print(table.concat(p,""))
+		if p[i] == "(" then
+			c = c + 1
+		else
+			c = c - 1
+			if c < 0 then
+				c = 0
+			else
+				local j = i
+				p[j] = "-"
+				while p[j] ~= "(" do
+					j = j - 1
+				end
+				p[j] = "-"
+				while p[j] == "-" do
+					j = j - 1
+					if j < 1 then
+						break
+					end
+				end
+				local d = i - j
+				if mx < d then
+					mx = d
+				end
+			end
+		end
+	end
+	--print(table.concat(p,""))
+	return mx
+end
+
+local lu = require("luaunit")
+
+function TestLp()
+	for inpt, otpt in pairs({
+		['(()())'] = 6,
+		[')()())'] = 4,
+		['((()))()(((()'] = 8,
+		['))))((()('] = 2,
+		['()(()'] = 2,
+		['((()(()()'] = 4,
+                ['((()(()())'] = 8,
+                ['()(()()'] = 4,
+                ['()(()())'] = 8}) do
+		--print(inpt, otpt)
+		lu.assertEquals(lp(inpt), otpt)
+	end
+end
+
+lu.run()
diff --git a/challenge-346/pokgopun/lua/ch-2.lua b/challenge-346/pokgopun/lua/ch-2.lua
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index 0000000000..16e4b82c78
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+++ b/challenge-346/pokgopun/lua/ch-2.lua
@@ -0,0 +1,161 @@
+--# https://theweeklychallenge.org/blog/perl-weekly-challenge-346/
+--[[
+
+Task 2: Magic Expression
+
+Submitted by: [45]Mohammad Sajid Anwar
+     __________________________________________________________________
+
+   You are given a string containing only digits and a target integer.
+
+   Write a script to insert binary operators +, - and * between the digits
+   in the given string that evaluates to target integer.
+
+Example 1
+
+Input: $str = "123", $target = 6
+Output: ("1*2*3", "1+2+3")
+
+Example 2
+
+Input: $str = "105", $target = 5
+Output: ("1*0+5", "10-5")
+
+Example 3
+
+Input: $str = "232", $target = 8
+Output: ("2*3+2", "2+3*2")
+
+Example 4
+
+Input: $str = "1234", $target = 10
+Output: ("1*2*3+4", "1+2+3+4")
+
+Example 5
+
+Input: $str = "1001", $target = 2
+Output: ("1+0*0+1", "1+0+0+1", "1+0-0+1", "1-0*0+1", "1-0+0+1", "1-0-0+1")
+     __________________________________________________________________
+
+   Last date to submit the solution 23:59 (UK Time) Sunday 9th November
+   2025.
+     __________________________________________________________________
+
+SO WHAT DO YOU THINK ?
+--]]
+--# solution by pokgopun@gmail.com
+
+local function segCmb(n, l, tmp) 
+	tmp = tmp or {}
+	if n == 1 then
+		table.insert(tmp,l)
+		coroutine.yield(tmp)
+	else
+		for s=1, l-1 do
+			local tmpc = table.move(tmp,1,#tmp,1,{})
+			table.insert(tmpc, s)
+			segCmb(n-1, l -s, tmpc)
+		end
+	end
+end
+
+local function evlCmb(n, dgtStr)
+	local iter = coroutine.wrap(function () segCmb(n, #dgtStr) end)
+	while true do
+		local seg = iter()
+		if not seg then
+			break
+		end
+		--print(table.concat(seg," "))
+		local res = {}
+		local b = 1
+		local i = 1
+		while i <= n do
+			local w = seg[i]
+			local s = dgtStr:sub(b,b+w-1)
+			if #s > 1 and s:sub(1,1) == "0" then
+				break
+			end
+			table.insert(res, s)
+			if i < n then
+				table.insert(res, "")
+			end
+			b = b + w
+			i = i + 1
+		end
+		if i > n then
+			--print(table.concat(res," "))
+			coroutine.yield(res)
+		end
+	end
+end
+
+local function bPowerN(b, n)
+	local v = 1
+	while n > 1 do
+		v = v * b
+		n = n - 1
+	end
+	return v
+end
+
+local function me(dgtStr, target)
+	local res = {}
+	local l = #dgtStr
+	if l < 2 then
+		return res
+	end
+	local ops = {"+", "-", "*"}
+	local b = #ops
+	for n=2, l do
+		local iter  = coroutine.wrap(function () evlCmb(n, dgtStr) end)
+		while true do
+			local evl = iter()
+			if not evl then
+				break
+			end
+			--print("->",table.concat(evl," "))
+			--print("power=",bPowerN(b, n)-1)
+			for d = 0, bPowerN(b, n)-1 do
+				--print("d=",d)
+				local i = 2*n
+				while d > 0 do
+					i = i - 2
+					--print("i=",i,ops[d%b+1])
+					evl[i] = ops[d%b+1]
+					d  = d // b
+				end
+				while i > 2 do
+					i = i - 2
+					--print("i=",i,ops[1])
+					evl[i] = ops[1]
+				end
+				local evlStr = table.concat(evl,"")
+				--print("=>",evlStr)
+				if load("return "..evlStr)() == target then
+					table.insert(res, evlStr)
+				end
+			end
+		end
+	end
+	table.sort(res)
+	--print(table.concat(res," "))
+	return res
+end
+
+local lu = require("luaunit")
+
+function TestMe()
+	for _, data in pairs({
+		{Input= {str = "123", target = 6},Output= {"1*2*3", "1+2+3"}},
+		{Input= {str = "105", target = 5},Output= {"1*0+5", "10-5"}},
+		{Input= {str = "232", target = 8},Output= {"2*3+2", "2+3*2"}},
+		{Input= {str = "1234", target = 10},Output= {"1*2*3+4", "1+2+3+4"}},
+		{Input= {str = "1001", target = 2},Output= {"1+0*0+1", "1+0+0+1", "1+0-0+1", "1-0*0+1", "1-0+0+1", "1-0-0+1"}}}) do
+		--{Input= {str = "1234567890", target = 1979}, Output= {'1+2*3+45*6*7-8+90','1+2-3+45*6*7+89+0','1+2-3+45*6*7+89-0'}},
+		--{Input= {str = "12304560789", target = 8532}, Output= {'1*2*30+4*5*60*7+8*9'}}}) do
+		lu.assertEquals(me(data.Input.str,data.Input.target),data.Output)
+	end
+end
+
+lu.run()