lf[i]代表从i往左递增序列的最大长度rg[i]代表从i往右递增序列的最大长度然后枚举每一个断点 #include <iostream> #include <vector> #include <map> #include <unordered_map> #include <algorithm> #include <set> #include <string> #include <sstream> #include <stack> #include <algorithm> #...