diff options
Diffstat (limited to 'number_subarr_odd_sum.c')
-rw-r--r-- | number_subarr_odd_sum.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/number_subarr_odd_sum.c b/number_subarr_odd_sum.c new file mode 100644 index 0000000..bcc1569 --- /dev/null +++ b/number_subarr_odd_sum.c @@ -0,0 +1,24 @@ +// 1524. Number of Sub-arrays With Odd Sum +#include "leetcode.h" + +/* + * given an array of integers 'arr', return the number of subarrays with an odd + * sum. since the answer can be very large, return it modulo 10e9+7. + */ + +int numOfSubarrays(int *arr, int arrSize) { + int curr = 0, ans = 0, cnt[] = {1, 0}, mod = 1e9 + 7; + for (int i = 0; i < arrSize; i++) { + curr ^= arr[i] & 1; + ans = (ans + cnt[1 - curr]) % mod; + cnt[curr]++; + } + return ans; +} + +int main() { + int a1[] = {1, 3, 5}, a2[] = {2, 4, 6}, a3[] = {1, 2, 3, 4, 5, 6, 7}; + printf("%d\n", numOfSubarrays(a1, ARRAY_SIZE(a1))); // expect: 4 + printf("%d\n", numOfSubarrays(a2, ARRAY_SIZE(a2))); // expect: 0 + printf("%d\n", numOfSubarrays(a3, ARRAY_SIZE(a3))); // expect: 16 +} |