giles 0231bb46a6 ocaml: phase 5.1 trapping_rain.ml baseline (LeetCode trapped water = 6) ...

Classic trapped-rain-water two-pass DP:

  left_max[i]  = max(heights[0..i])    (forward sweep)
  right_max[i] = max(heights[i..n-1])  (downto sweep)
  water        = sum over i of (min(left_max[i], right_max[i])
                                  - heights[i])

For [0; 1; 0; 2; 1; 0; 1; 3; 2; 1; 2; 1]: water = 6.

Tests dual sweep (forward + downto), array of running maxes,
inline-if rhs of <- for running-max update (uses iter-236 fix
for <- accepting if/match RHS).

203 baseline programs total.

2026-05-11 05:54:39 +00:00

4.6 KiB

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