Andi Gu's Solution

solution.py

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+def derivative(x):  # Derivative function of polynomial
+    ans = 0
+    for i in range(n):
+        degree = n - i - 1
+        ans += degree * cash_flow[i] * x ** (degree - 1)
+    return ans
+
+
+def f(x):  # Polynomial
+    ans = 0
+    for i in range(n):
+        degree = n - i - 1
+        ans += cash_flow[i] * x ** degree
+    ans -= market_value[-1]  # Last market value
+    return ans
+
+
+def solution():
+    current = 1.5  # Guess for initial interest (current = 1 + x, therefore initial guess is 0.5%)
+    x = 500  # Adjust to higher value for more precision
+    for i in range(x):
+        current = current - (f(current) / derivative(current))
+    return current - 1
+
+
+data = open("test2.csv").readlines()
+cash_flow = []
+market_value = []
+for line in data[1:]:
+    a, b, c = [float(i) for i in line.split(",")]
+    cash_flow.append(b)
+    market_value.append(c)
+n = len(cash_flow)
+print(solution())

test2.csv

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+
+0,1000,1000
+1,1500,2600
+2,0,2700
+3,0,3000
+4,0,3400
+5,0,3806