Prefix Sums & Binary Search Checkpoint

1. Range sum using prefix sums is:

pref[r+1] - pref[l] pref[r] - pref[l] pref[l] - pref[r] pref[r] + pref[l]

2. When counting subarrays with sum k, counts[0] should start as:

3. Difference array update for inclusive [l, r] with delta is:

diff[l] += delta, diff[r+1] -= delta diff[l] -= delta, diff[r] += delta diff[l] += delta only diff[r] -= delta only

4. Binary search on answer requires the predicate to be ____.

5. For shipping capacity, the lower bound is:

max(weights) sum(weights) min(weights) 0