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Diffstat (limited to 'num_subseq_satisfy.py')
-rw-r--r-- | num_subseq_satisfy.py | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/num_subseq_satisfy.py b/num_subseq_satisfy.py new file mode 100644 index 0000000..2f3889c --- /dev/null +++ b/num_subseq_satisfy.py @@ -0,0 +1,36 @@ +# 1498. Number of Subsequences That Satisfy the Given Sum Condition + +""" +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(object): + def numSubseq(self, nums, target): + """ + :type nums: List[int] + :type target: int + :rtype: int + """ + pows, mod = [1], 10**9 + 7 + nums.sort() + for i in range(1, len(nums)): + pows.append((pows[-1] << 1) % mod) + ans, l, r = 0, 0, len(nums) - 1 + while l <= r: + if nums[l] + nums[r] > target: + r -= 1 + continue + ans = (ans + pows[r - l]) % mod + l += 1 + return ans + + +if __name__ == "__main__": + obj = Solution() + print(obj.numSubseq(nums=[3, 5, 6, 7], target=9)) + print(obj.numSubseq(nums=[3, 3, 6, 8], target=10)) + print(obj.numSubseq(nums=[2, 3, 3, 4, 6, 7], target=12)) |