Update README with LeetCode Daily Challenge

Author: jeremymanning

README.md

@@ -289,6 +289,7 @@ _**Note:** Our group is currently taking a break from grinding leetcode. The tab
 | April 2, 2025 | [2873](https://leetcode.com/problems/maximum-value-of-an-ordered-triplet-i/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/2873) | 🟢 Easy |
 | April 3, 2025 | [2874](https://leetcode.com/problems/maximum-value-of-an-ordered-triplet-ii/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/2874) | 🟡 Medium |
 | April 4, 2025 | [1123](https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1123) | 🟡 Medium |
+| April 5, 2025 | [1863](https://leetcode.com/problems/sum-of-all-subset-xor-totals/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1863) | 🟢 Easy |
 
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