回答此问题可获得 20 贡献值,回答如果被采纳可获得 50 分。
<pre><code>def fastMaxVal(w, v, i, aW):
global numCalls
numCalls += 1
try: return m[(i, aW)]
except KeyError:
if i == 0:
if w[i] <= aW:
m[(i, aW)] = v[i]
return v[i]
else:
m[(i, aW)] = 0
return 0
without_i = fastMaxVal(w, v, i-1, aW)
if w[i] > aW:
m[(i, aW)] = without_i
return without_i
else:
with_i = v[i] + fastMaxVal(w, v, i-1, aW - w[i])
res = max(with_i, without_i)
m[(i, aW)] = res
return res
def maxVal0(w, v, i, aW):
m = {}
return fastMaxVal
weights = [1, 1, 5, 5, 3, 3, 4, 4]
vals = [15, 15, 10, 10, 9, 9, 5, 5]
numCalls = 0
res = maxVal0(weights, vals, len(vals) - 1, 8)
print ('max Val =', res, 'number of calls =', numCalls)
</code></pre>
<p>这个程序是关于背包问题的。我用决策树来解决这个问题。但是,我运行了这个程序,得到了以下结果</p>
<blockquote>
<p>max Val = function fastMaxVal at 0x03BB7390 number of calls = 0</p>
</blockquote>
<p>我的程序怎么了</p>