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Diffstat (limited to 'range_sum_sorted_subarr.py')
-rw-r--r-- | range_sum_sorted_subarr.py | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/range_sum_sorted_subarr.py b/range_sum_sorted_subarr.py new file mode 100644 index 0000000..81e28ce --- /dev/null +++ b/range_sum_sorted_subarr.py @@ -0,0 +1,61 @@ +# 1508. Range Sum of Sorted Subarray Sums + +""" +you are given the array 'nums' consisting of 'n' positive integers. you +computed the sum of all non empty continuous subarrays from the array and +then sorted them in non decreasing order, creating a new array of 'n (n + +1) / 2' numbers. return the sum of the numbers from index 'left' to index +'right' inclusive, in the new array. since the answer may be very large, +return it modulo 1e9+7 +""" + + +class Solution(object): + def rangeSum(self, nums, n, left, right): + """ + :type nums: List[int] + :type n: int + :type left: int + :type right: int + :rtype: int + """ + b, c = [0] * (n + 1), [0] * (n + 1) + for i in range(n): + b[i + 1] = b[i] + nums[i] + c[i + 1] = c[i] + b[i + 1] + + def cnt_sum_und(score): + res, i = 0, 0 + for j in range(n + 1): + while b[j] - b[i] > score: + i += 1 + res += j - i + return res + + def kth_score(k): + l, r = 0, b[n] + while l < r: + m = (l + r) / 2 + if cnt_sum_und(m) < k: + l = m + 1 + else: + r = m + return l + + def sum_k_sums(k): + score = kth_score(k) + res, i = 0, 0 + for j in range(n + 1): + while b[j] - b[i] > score: + i += 1 + res += b[j] * (j - i + 1) - (c[j] - (c[i - 1] if i else 0)) + return res - (cnt_sum_und(score) - k) * score + + return sum_k_sums(right) - sum_k_sums(left - 1) + + +if __name__ == "__main__": + obj = Solution() + print(obj.rangeSum(nums=[1, 2, 3, 4], n=4, left=1, right=5)) + print(obj.rangeSum(nums=[1, 2, 3, 4], n=4, left=3, right=4)) + print(obj.rangeSum(nums=[1, 2, 3, 4], n=4, left=1, right=10)) |