diff --git a/cpp/2207/220703.cpp b/cpp/2207/220703.cpp new file mode 100644 index 0000000..c615ce1 --- /dev/null +++ b/cpp/2207/220703.cpp @@ -0,0 +1,33 @@ +#include +#include +#include + +/** + * 376. Wiggle Subsequence + * A wiggle sequence is a sequence where the differences between successive numbers strictly alternate between positive and negative. The first difference (if one exists) may be either positive or negative. A sequence with one element and a sequence with two non-equal elements are trivially wiggle sequences. + * For example, [1, 7, 4, 9, 2, 5] is a wiggle sequence because the differences (6, -3, 5, -7, 3) alternate between positive and negative. + * In contrast, [1, 4, 7, 2, 5] and [1, 7, 4, 5, 5] are not wiggle sequences. The first is not because its first two differences are positive, and the second is not because its last difference is zero. + * A subsequence is obtained by deleting some elements (possibly zero) from the original sequence, leaving the remaining elements in their original order. + * Given an integer array nums, return the length of the longest wiggle subsequence of nums. + */ + +class Solution { +public: + static int wiggleMaxLength(const std::vector& nums) { + const int n = nums.size(); + if (n <= 1) + return 1; + int dp[2][1024]{{1}, {1}}; + for (int i = 1; i < n; ++i) { + const int t = nums[i] - nums[i - 1]; + dp[0][i] = t > 0 ? 1 + dp[1][i - 1] : dp[0][i - 1]; + dp[1][i] = t < 0 ? 1 + dp[0][i - 1] : dp[1][i - 1]; + } + return std::max(dp[0][n - 1], dp[1][n - 1]); + } +}; + +int main() { + std::cout << Solution::wiggleMaxLength({1,17,5,10,13,15,10,5,16,8}); + return 0; +} diff --git a/cpp/2207/CMakeLists.txt b/cpp/2207/CMakeLists.txt index bdd99d3..e9bb72e 100644 --- a/cpp/2207/CMakeLists.txt +++ b/cpp/2207/CMakeLists.txt @@ -3,4 +3,4 @@ PROJECT(2207) SET(CMAKE_CXX_STANDARD 23) -ADD_EXECUTABLE(2207 220703-CN.cpp) +ADD_EXECUTABLE(2207 220703.cpp)