Update README with LeetCode Daily Challenge

Author: jeremymanning

README.md

@@ -104,6 +104,7 @@ _**Note:** Our group is currently taking a break from grinding leetcode. The tab
 | September 29, 2024 | [432](https://leetcode.com/problems/all-oone-data-structure/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/432) | 🔴 Hard |
 | September 30, 2024 | [1381](https://leetcode.com/problems/design-a-stack-with-increment-operation/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1381) | 🟡 Medium |
 | October 1, 2024 | [1497](https://leetcode.com/problems/check-if-array-pairs-are-divisible-by-k/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1497) | 🟡 Medium |
+| October 2, 2024 | [1331](https://leetcode.com/problems/rank-transform-of-an-array/description/?envType=daily-question) | [Click here](https://github.com/ContextLab/leetcode-solutions/tree/main/problems/1331) | 🟢 Easy |
 
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