1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
// 2090. K Radius Subarray Averages
#include <stdio.h>
#include <stdlib.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.
*/
int *getAverages(int *nums, int nums_size, int k, int *return_size) {
int n = nums_size, d = 2 * k + 1;
int *ans = malloc(n * sizeof(int));
*return_size = n;
long long sum = 0;
if (n < d) {
for (int i = 0; i < n; i++)
ans[i] = -1;
return ans;
}
for (int i = 0; i < k; i++) {
ans[i] = -1;
sum += nums[i];
}
sum += nums[k];
for (int i = k + 1; i < 2 * k + 1; i++)
sum += nums[i];
ans[k] = sum / d;
for (int i = k + 1; i < n - k; i++) {
int d = nums[i + k] - nums[i - k - 1];
if (!d)
ans[i] = ans[i - 1];
else {
sum += d;
ans[i] = sum / d;
}
}
for (int i = 0; i < k; i++)
ans[n - 1 - i] = -1;
return ans;
}
int main() {
int n1[] = {7, 4, 3, 9, 1, 8, 5, 2, 6}, ns1 = 9, k1 = 3, rs1[] = {};
int n2[] = {100000}, ns2 = 1, k2 = 0, rs2[] = {};
int n3[] = {8}, ns3 = 1, k3 = 100000, rs3[] = {};
int *ga1 = getAverages(n1, ns1, k1, rs1);
int *ga2 = getAverages(n2, ns2, k2, rs2);
int *ga3 = getAverages(n3, ns3, k3, rs3);
for (int i = 0; i < ns1; i++)
printf("%d ", ga1[i]); // expect: -1,-1,-1,5,4,4,-1,-1,-1
printf("\n");
for (int i = 0; i < ns2; i++)
printf("%d ", ga2[i]); // expect: 100000
printf("\n");
for (int i = 0; i < ns3; i++)
printf("%d ", ga3[i]); // expect: -1
printf("\n");
}
|