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author | jack <[email protected]> | 2024-06-14 13:13:15 -0600 |
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committer | jack <[email protected]> | 2024-06-14 13:13:15 -0600 |
commit | d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch) | |
tree | 96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /subarr_sums_div_k.c | |
download | leetcode-d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa.tar.gz leetcode-d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa.zip |
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Diffstat (limited to 'subarr_sums_div_k.c')
-rw-r--r-- | subarr_sums_div_k.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/subarr_sums_div_k.c b/subarr_sums_div_k.c new file mode 100644 index 0000000..46dce84 --- /dev/null +++ b/subarr_sums_div_k.c @@ -0,0 +1,30 @@ +// 974. Subarray Sums Divisible by K +#include "leetcode.h" + +/* + * given an integer array 'nums' and an integer 'k', return the number of non + * empty subarrays that have a sum divisible by 'k'. a subarray is contiguous + * part of an array. + */ + +int subarraysDivByK(int *nums, int numsSize, int k) { + int n = numsSize, sum = 0, ans = 0; + int *hash = (int *)calloc(k, sizeof(int)); + hash[0] = 1; + for (int i = 0; i < n; i++) { + sum += nums[i]; + int val = sum + 10000 * k; + while (val < 0) + val += k; + ans += hash[val % k]; + hash[val % k]++; + } + free(hash); + return ans; +} + +int main() { + int n1[] = {4, 5, 0, -2, -3, 1}, n2[] = {5}; + printf("%d\n", subarraysDivByK(n1, ARRAY_SIZE(n1), 5)); // expect: 7 + printf("%d\n", subarraysDivByK(n2, ARRAY_SIZE(n2), 9)); // expect: 0 +} |