https://h30306.github.io/blog/tags/brainteaser/Recent content in Brainteaser onHugo -- gohugo.ioenhwork0511@gmail.com (Wei Yi Chung)hwork0511@gmail.com (Wei Yi Chung)© 2026 Wei Yi ChungTue, 20 Oct 2026 00:00:00 +0000https://h30306.github.io/blog/algorithm/math/Tue, 20 Oct 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/algorithm/math/Combinatorial counting (pairs, ways to split), building the k-th permutation digit by digit, geometry (nearest point, law of cosines, triangle inequality), problems that become formulas after sorting or an observation, plus carry arithmetic, base conversion and fast exponentiationhttps://h30306.github.io/blog/leetcode/leetcode-3828/Sun, 01 Feb 2026 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-3828/LeetCode 3828 note: Alice can leave only the first or last element on her first move, guaranteeing max(first, last); Bob can likewise keep only an end, and one deletion changes at most one end, so the answer is max(first, last)https://h30306.github.io/blog/leetcode/leetcode-2745/Tue, 22 Jul 2025 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-2745/LeetCode 2745 note: AA and BB must alternate, using min(x, y) pairs plus one extra of the more common kind, and every AB fits inhttps://h30306.github.io/blog/leetcode/leetcode-1025/Tue, 27 Sep 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-1025/LeetCode 1025 note: dp[i] holds when some divisor x of i makes dp[i - x] a loss; observing the pattern, the answer is simply whether n is evenhttps://h30306.github.io/blog/leetcode/leetcode-292/Tue, 23 Aug 2022 00:00:00 +0000hwork0511@gmail.com (Wei Yi Chung)https://h30306.github.io/blog/leetcode/leetcode-292/LeetCode 292 note: whoever faces a multiple of 4 stones loses, so the first player wins when n % 4 != 0