Update README with LeetCode Daily Challenge

Author: jeremymanning

README.md

@@ -214,6 +214,7 @@ _**Note:** Our group is currently taking a break from grinding leetcode. The tab
 | January 17, 2025 | [2683](https://leetcode.com/problems/neighboring-bitwise-xor/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/2683) | 🟡 Medium |
 | January 18, 2025 | [1368](https://leetcode.com/problems/minimum-cost-to-make-at-least-one-valid-path-in-a-grid/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1368) | 🔴 Hard |
 | January 19, 2025 | [407](https://leetcode.com/problems/trapping-rain-water-ii/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/407) | 🔴 Hard |
+| January 20, 2025 | [2661](https://leetcode.com/problems/first-completely-painted-row-or-column/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/2661) | 🟡 Medium |
 
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