第三题其实就是求最长递增子序列 class Solution: def maxEnvelopes(self, envelopes: List[List[int]]) -> int: if not envelopes: return 0 envelopes.sort() dp=[1]*len(envelopes) for i in range(len(envelopes)): for j in range(i): if envelopes[i][0]>envelopes[j][0] and envelopes[i][1]>envelopes[j][1]: dp[i]=max(dp[i],dp[j]+1) num=max(dp) return num