C : 4-lines - simple n short - no built-in Utils/Data Structures, etc
\nint findPairs(int* nums, int numsSize, int k){\n    char a[200000] = { 0 }, *m = &a[500];\n    for (int i = 0, c = 0, *n = nums ; i < numsSize || (numsSize = 
```\nint findPairs(int* nums, int numsSize, int k){\n    char a[200000] = { 0 }, *m = &a[500];\n    for (int i = 0, c = 0, *n = nums ; i < numsSize || (numsSize = c, 0) ; i++)\n        for (int j = i, p ; ++j < numsSize ; abs(n[i] - n[j]) == k && !m[p = n[i] + n[j]] ? c += m[p] = 1 : 0);\n    return numsSize;\n}\n```
['C']