请完善以下代码：
import matplotlib.pyplot as plt, numpy as np
x = np.linspace(0, 1, 20) # x是0，0.05,0.1...
y1 = x * x
plt._________()
plt.rcParams[.font.sans-serif.] = .SimHei.
plt.plot(x, y1, color=.green., marker=.o.)
plt.xlabel(.节点数(*100).)
plt.ylabel(.能耗(J).)
plt.show()