下午做力扣上的动态规划添加链接描述，做了两三个小时才通过了。把思路简单概括。
首先创建出一个三维dp数组，在每个维度上的第0维进行初始化，我的问题一直出在初始化上面，三维比二维感觉要复杂不少。状态转移方程是一个套话，做多了直接写出来了。

class Solution(object):def findMaxForm(self, strs, m, n):""":type strs: List[str]:type m: int:type n: int:rtype: int"""def element(strd):zero = 0one = 0for i in strd:if i == "0":zero = zero + 1elif i == "1":one = one + 1return zero, onedp = [[[None] * (n + 1) for _ in range(m + 1)] for _ in range(len(strs))]dp[0][0][0] = 0for i in range(1, len(strs)):dp[i][0][0] = 0for i in range(0, len(strs)):for j in range(1, n + 1):zero, one = element(strs[i])if zero == 0 and one <= j:if i != 0:dp[i][0][j] = max(dp[i - 1][0][j], dp[i - 1][0][j - one]+1)else:dp[i][0][j] = 1else:if i==0:dp[i][0][j] = 0else:dp[i][0][j] = dp[i-1][0][j]for i in range(0, len(strs)):for j in range(1, m + 1):zero, one = element(strs[i])if one == 0 and zero <= j:if i != 0:dp[i][j][0] = max(dp[i - 1][j][0], dp[i - 1][j - zero][0]+1)else:dp[i][j][0] = 1else:if i==0:dp[i][j][0] = 0else:dp[i][j][0] = dp[i-1][j][0]for i in range(0, m + 1):for j in range(0, n + 1):zero, one = element(strs[0])if zero <= i and one <= j:dp[0][i][j] = 1else:dp[0][i][j] = 0for i in range(1, len(strs)):zero, one = element(strs[i])for j in range(1, m + 1):for k in range(1, n + 1):if j >= zero and k >= one:dp[i][j][k] = max(dp[i - 1][j][k], dp[i - 1][j - zero][k - one] + 1)else:dp[i][j][k] = dp[i - 1][j][k]return dp[len(strs) - 1][m][n]

舞台再大，没有勇气上台也永远是个观众。