# q4_3b.py
import json
import matplotlib.pyplot as plt

with open("../q4_2/movies.json", "r", encoding="utf-8") as f:
    data = json.load(f)

movies = data["movies"]

durations = []
for m in movies:
    durations.append(m["duration"])

plt.hist(durations, bins=5, color="green")
plt.title("时长分布")
plt.xlabel("时长（分钟）")

plt.savefig("q4_3b_hist.png", dpi=150)
plt.close()

print("✅ 时长直方图生成成功！")