A ledger worth checking

MediumArraysHash mapsPrefix sums

The brewery's ledger records signed token adjustments in order: positive entries add tokens, negative entries refund them, and zero entries leave the balance unchanged. An audit strip is any nonempty contiguous section of the ledger. Count how many audit strips have a total exactly equal to target. Strips with different start or end positions count separately, even when their values are identical. Return the count, not the strips.

Example 1

INPUT[3,-1,-2,3], 3OUTPUT3

The strips at inclusive index ranges [0, 0], [0, 3], and [3, 3] each total 3.

Example 2

INPUT[0,0,0], 0OUTPUT6

All three length-1 strips, both length-2 strips, and the full length-3 strip total zero.

Keep in mind

0 <= adjustments.length <= 20,000
Each adjustment is an integer from -1,000 to 1,000.
target is an integer from -20,000,000 to 20,000,000.
The result fits exactly in a JavaScript Number.

/** @param {number[]} adjustments
 *  @param {number} target
 *  @returns {number} */
function solve(adjustments, target) {
  // Count nonempty contiguous strips whose total is target.
}

/** @param {number[]} adjustments
 *  @param {number} target
 *  @returns {number} */
function solve(adjustments, target) {
  // Count nonempty contiguous strips whose total is target.
}

INPUT[3,-1,-2,3], 3

EXPECTED OUTPUT3

Public samples only. These checks do not award ranked points.

AFTER THE SOLVE

How the solution works.

Walk through a solution, check its time and space costs, and compare it with yours.

Checking your progress…

A ledger worth checking

Example 1

Example 2

Keep in mind

How the solution works.

Related problems

A perfect pair

Flights with a precise mix