---
changelog:
  category: Release
  version: 20260925.180040.000000000
date: '2026-09-25T18:00:40Z'
seo:
  description: >-
    Finished Fri, Sep 25, 2026, 2:00 PM ET: all 3 core problems closed, 3
    problems closed that day. Scheduled: Fri Sep 25, 2026 · Phase: Phase V —
    Decision Space…
title: Topic 21 — 1-D Dynamic Programming
type: changelog
---
<!-- release-topics: #23 -->
Finished Fri, Sep 25, 2026, 2:00 PM ET: all 3 core problems closed, 3 problems closed that day.

**Scheduled:** Fri Sep 25, 2026 · **Phase:** Phase V — Decision Space · **Topic:** #23 · **Builds on:** Topic 20

## Closed Sep 25 — the day the topic finished

| Issue | Problem | Set | Difficulty | Closed (ET) | Solution |
| --- | --- | --- | --- | --- | --- |
| #157 | LC 70 · Climbing Stairs | core | easy | Sep 25 | [py](https://github.com/prdlk/leetcode/blob/20260925.180040.000000000/work/1/Easy/Math/70.climbing-stairs.py) · [docs](https://lc.prd.lk/70) |
| #158 | LC 198 · House Robber | core | medium | Sep 25 | [py](https://github.com/prdlk/leetcode/blob/20260925.180040.000000000/work/1/Medium/Array/198.house-robber.py) · [docs](https://lc.prd.lk/198) |
| #159 | LC 322 · Coin Change | core | medium | Sep 25 | [py](https://github.com/prdlk/leetcode/blob/20260925.180040.000000000/work/1/Medium/Array/322.coin-change.py) · [docs](https://lc.prd.lk/322) |

## Open at release

| Issue | Problem | Set | Difficulty | Closed (ET) | Solution |
| --- | --- | --- | --- | --- | --- |
| #160 | LC 746 · Min Cost Climbing Stairs | optional | easy | — | — |
| #161 | LC 213 · House Robber II | optional | medium | — | — |
| #162 | LC 300 · Longest Increasing Subsequence | optional | medium | — | — |
| #163 | LC 139 · Word Break | optional | medium | — | — |
| #164 | LC 91 · Decode Ways | optional | medium | — | — |
| #165 | LC 647 · Palindromic Substrings | optional | medium | — | — |
| #222 | LC 494 · Target Sum | optional | medium | — | — |

---

`20260925.180040.000000000` is [timever](https://gist.github.com/twolfson/de1b004dd22536b8e668) for the UTC instant the core set completed; it tags 6f9e4ec, the last main commit before it.