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Diffstat (limited to 'other/k_radius_subarr.cpp')
-rw-r--r-- | other/k_radius_subarr.cpp | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/other/k_radius_subarr.cpp b/other/k_radius_subarr.cpp new file mode 100644 index 0000000..91184bb --- /dev/null +++ b/other/k_radius_subarr.cpp @@ -0,0 +1,45 @@ +// 2090. K Radius Subarray Averages +#include "leetcode.h" + +/* + * given a 0-indexed array 'nums' of 'n' integers, and an integer 'k'. the + * k-radius average for a subarray of 'nums' centered at some index 'i' with the + * radius 'k' is the average of all elements in 'nums' between the indices 'i - + * k' and 'i + k' (inclusive). if there are less than 'k' elements before or + * after the index 'i', then the k-radius average is -1. build and return 'avgs' + * of length 'n' where 'avgs[i]' is the k-radius average for the subarray + * centered at index 'i'. the average of 'x' elements is the sum of the 'x' + * elements divided by 'x', using integer division. the integer division + * truncates toward zero, which means losing its fractional part. + */ + +class Solution { +public: + vector<int> getAverages(vector<int> &nums, int k) { + vector<int> ans(nums.size(), -1); + long long sum = 0, d = k * 2 + 1; + for (int i = 0; i < nums.size(); ++i) { + sum += nums[i]; + if (i + 1 >= d) { + if (i >= d) + sum -= nums[i - d]; + ans[i - d / 2] = sum / d; + } + } + return ans; + } +}; + +int main() { + Solution obj; + vector<int> n1 = {7, 4, 3, 9, 1, 8, 5, 2, 6}, n2 = {100000}, n3 = {8}; + for (auto i : obj.getAverages(n1, 3)) + printf("%d ", i); // expect: -1,-1,-1,5,4,4,-1,-1,-1 + printf("\n"); + for (auto i : obj.getAverages(n2, 0)) + printf("%d ", i); // expect: 100000 + printf("\n"); + for (auto i : obj.getAverages(n3, 100000)) + printf("%d ", i); // expect: -1 + printf("\n"); +} |