# 第六章 - 高频考题（困难） # 困难难度题目合集 困难难度题目从类型上说多是： - 图 - 设计题 - 游戏场景题目 - 中等题目的 follow up 从解法上来说，多是： - 图算法 - 动态规划 - 二分法 - DFS & BFS - 状态压缩 - 剪枝 从逻辑上说， 要么就是非常难想到，要么就是非常难写代码。 这里我总结了几个技巧： 1. 看题目的数据范围， 看能否暴力模拟 2. 暴力枚举所有可能的算法往上套 3. 总结和记忆解题模板，减少解题压力 4. [0004.median-of-two-sorted-array](4.median-of-two-sorted-arrays.html) 5. [0023.merge-k-sorted-lists](23.merge-k-sorted-lists.html) 6. [0025.reverse-nodes-in-k-group](../problems/25.reverse-nodes-in-k-groups-cn.md) 7. [0030.substring-with-concatenation-of-all-words](30.substring-with-concatenation-of-all-words.html) 8. [0032.longest-valid-parentheses](32.longest-valid-parentheses.html) 9. [0042.trapping-rain-water](42.trapping-rain-water.html)🖊 10. [0052.N-Queens-II](52.N-Queens-II.html) 11. [0084.largest-rectangle-in-histogram](84.largest-rectangle-in-histogram.html) 12. [0085.maximal-rectangle](85.maximal-rectangle.html) 13. [0124.binary-tree-maximum-path-sum](124.binary-tree-maximum-path-sum.html) 14. [0128.longest-consecutive-sequence](128.longest-consecutive-sequence.html) 15. [0145.binary-tree-postorder-traversal](145.binary-tree-postorder-traversal.html) 16. [0212.word-search-ii](212.word-search-ii.html) 17. [0239.sliding-window-maximum](239.sliding-window-maximum.html) 18. [0295.find-median-from-data-stream](295.find-median-from-data-stream.html) 19. [0301.remove-invalid-parentheses](301.remove-invalid-parentheses.html) 20. [0312.burst-balloons](312.burst-balloons.html) 🆕 21. [0335.self-crossPing](335.self-crossing.html) 22. [0460.lfu-cache](460.lfu-cache.html) 23. [0472.concatenated-words](472.concatenated-words.html) 🆕 24. [0488.zuma-game.md](488.zuma-game.html) 🆕 25. [0493.reverse-pairs](493.reverse-pairs.html) 🆕 26. [0887.super-egg-drop](887.super-egg-drop.html) 27. [0895.maximum-frequency-stack](895.maximum-frequency-stack.html) 🆕 28. [1032.stream-of-characters](1032.stream-of-characters.html) 🆕 29. [1168.optimize-water-distribution-in-a-village](../problems/1168.optimize-water-distribution-in-a-village-cn.md) 🆕 30. [1449.form-largest-integer-with-digits-that-add-up-to-target](1449.form-largest-integer-with-digits-that-add-up-to-target.html) 🆕