you give 0indexe strictly increase integer array num positive integer diff a triplet j k arithmetic triplet follow condition meti j knumsj numsi diff andnumsk numsj diffreturn number unique arithmetic triplet Example 1input num 0146710 diff 3output 2explanation1 2 4 arithmetic triplet 7 4 3 4 1 32 4 5 arithmetic triplet 10 7 3 7 4 3 Example 2input num 456789 diff 2Output 2explanation0 2 4 arithmetic triplet 8 6 2 6 4 21 3 5 arithmetic triplet 9 7 2 7 5 2 constraints3 numslength 2000 numsi 2001 diff 50nums strictly increase