##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
HashMap technique trace
Count subarrays summing to in . Use prefix sums with a hashmap. As you compute prefix sums, track how many times each sum occurred.
At each position, add to the answer. Prefix sums: . At sum : , add . At sum : , add . At sum : , add . At sum : , add . Total: subarrays. They are: , , , .
