DSA — Stacks & Queues

1 Sum of array elements Easy 2 Find maximum in array Easy 3 Reverse an array in-place Medium 4 Count occurrences of element Easy 5 Second largest element Medium 6 Valid parentheses depth #1 Easy 7 Queue — simulate task scheduler #2 Medium 8 Valid parentheses depth #3 Easy 9 Queue — simulate task scheduler #4 Medium 10 Valid parentheses depth #5 Easy 11 Queue — simulate task scheduler #6 Medium 12 Valid parentheses depth #7 Easy 13 Queue — simulate task scheduler #8 Medium 14 Valid parentheses depth #9 Easy 15 Queue — simulate task scheduler #10 Medium 16 Valid parentheses depth #11 Easy 17 Queue — simulate task scheduler #12 Medium 18 Valid parentheses depth #13 Easy 19 Queue — simulate task scheduler #14 Medium 20 Valid parentheses depth #15 Easy 21 Queue — simulate task scheduler #16 Medium 22 Valid parentheses depth #17 Easy 23 Queue — simulate task scheduler #18 Medium 24 Valid parentheses depth #19 Easy 25 Queue — simulate task scheduler #20 Medium 26 Valid parentheses depth #21 Easy 27 Queue — simulate task scheduler #22 Medium 28 Valid parentheses depth #23 Easy 29 Queue — simulate task scheduler #24 Medium 30 Valid parentheses depth #25 Easy 31 Queue — simulate task scheduler #26 Medium 32 Valid parentheses depth #27 Easy 33 Queue — simulate task scheduler #28 Medium 34 Valid parentheses depth #29 Easy 35 Queue — simulate task scheduler #30 Medium 36 Valid parentheses depth #31 Easy 37 Queue — simulate task scheduler #32 Medium 38 Valid parentheses depth #33 Easy 39 Queue — simulate task scheduler #34 Medium 40 Valid parentheses depth #35 Easy 41 Queue — simulate task scheduler #36 Medium 42 Valid parentheses depth #37 Easy 43 Queue — simulate task scheduler #38 Medium 44 Valid parentheses depth #39 Easy 45 Queue — simulate task scheduler #40 Medium 46 Valid parentheses depth #41 Easy 47 Queue — simulate task scheduler #42 Medium 48 Valid parentheses depth #43 Easy 49 Queue — simulate task scheduler #44 Medium 50 Valid parentheses depth #45 Easy