diff options
Diffstat (limited to 'other/num_subseq_satisfy.cpp')
-rw-r--r-- | other/num_subseq_satisfy.cpp | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/other/num_subseq_satisfy.cpp b/other/num_subseq_satisfy.cpp new file mode 100644 index 0000000..6eb1a12 --- /dev/null +++ b/other/num_subseq_satisfy.cpp @@ -0,0 +1,34 @@ +// 1498. Number of Subsequences That Satisfy the Given Sum Condition +#include "leetcode.h" + +/* + * given an array of integers 'nums' and an integer 'target' + * return the numbe of non-empty subsequences of 'nums' such + * that the sum of the minimum and maximum element on it is + * less or equal to 'target'. return modulo 10^9+7 + */ + +class Solution { +public: + int numSubSeq(vector<int> &nums, int target) { + int ans = 0, mod = 1000000007; + vector<int> pre = {0, 1}; + for (auto i = pre.size(); i <= nums.size(); ++i) + pre.push_back((pre.back() << 1) % mod); + sort(nums.begin(), nums.end()); + for (int i = 0, j = nums.size() - 1; i <= j; ++i) { + while (i <= j && nums[i] + nums[j] > target) + --j; + ans = (ans + pre[j - i + 1]) % mod; + } + return ans; + } +}; + +int main() { + Solution obj; + vector<int> n1 = {3, 5, 6, 7}, n2 = {3, 3, 6, 8}, n3 = {2, 3, 3, 4, 6, 7}; + printf("%d\n", obj.numSubSeq(n1, 9)); // expect: 4 + printf("%d\n", obj.numSubSeq(n2, 10)); // expect: 6 + printf("%d\n", obj.numSubSeq(n3, 12)); // expect: 61 +} |