Can someone give hints for the third and the fourth problems for the Codechef October Lunctime. ↵
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[Codechef October Lunchtime](https://www.codechef.com/LTIME53)↵
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[Problem 3](https://www.codechef.com/LTIME53/problems/WEICOM)↵
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[Problem 4](https://www.codechef.com/LTIME53/problems/OPTSSET) 4
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[Codechef October Lunchtime](https://www.codechef.com/LTIME53)↵
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[Problem 3](https://www.codechef.com/LTIME53/problems/WEICOM)↵
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[Problem 4](https://www.codechef.com/LTIME53/problems/OPTSSET)