1 files changed, 5 insertions(+), 4 deletions(-)

M 2023/9.lua

@@ 21,18 21,19 @@ In general
 	P(-1) = sum i ∈ [0, n - 1] of (-1)^i       * binom(n, i + 1) * value[i]
 --]]
 
-local line, sign, coeffs, ans1, ans2 = io.read(), -1, {1}, 0, 0
+local line, coeffs = io.read(), {-1}
 for _ in line:gmatch('-?%d+') do
+	coeffs[#coeffs + 1] = 0
 	for i = #coeffs, 2, -1 do
 		coeffs[i] = coeffs[i] - coeffs[i - 1]
 	end
-	coeffs[#coeffs + 1], sign = sign, -sign
 end
+local ans1, ans2 = 0, 0
 repeat
 	local i = 1
 	for value in line:gmatch('-?%d+') do
-		ans1, i = ans1 + value * coeffs[i] * sign, i + 1
-		ans2    = ans2 - value * coeffs[i]
+		ans1, i = ans1 + value * coeffs[#coeffs - i + 1], i + 1
+		ans2    = ans2 + value * coeffs[i]
 	end
 	line = io.read()
 until not line