2nd Annual Harvard-MIT November Tournament #0ix9
2nd Annual Harvard-MIT November TournamentHard
From module Advanced Inequalities
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Understand the scale
Scale
0.5: Easiest math competition problems, often solvable even for early middle school students without experience.
1: Problems strictly for beginners, often at a moderate middle school level.
1.5: Problems for stronger beginner students, on the level of the middling problems in most middle school contests.
2: For motivated beginners, harder questions from the previous categories.
2.5: More advanced beginner problems, hardest questions from previous categories.
3: Early intermediate problems that require more creative thinking.
3.5: Tougher early intermediate problems that consistently stretch into higher-level creative thinking or conceptual knowledge.
4: Intermediate-level problems.
4.5: Upper intermediate problems approaching the upper bound for non-invitational sprint math competitions.
5: More difficult AIME problems or simple proof-based Olympiad-style problems.
6: High-level AIME-styled questions or introductory Olympiad-level questions.
7: Tougher Olympiad-level questions, may require more technical knowledge.
8: High-level Olympiad-level questions.
9: Expert Olympiad-level questions.
9.5: The hardest problems appearing on Olympiads which the strongest students could reasonably solve.
10: Historically notorious problems, generally unsuitable for even very hard competitions because they are exceedingly tedious, long, and difficult.
AlgorithmsInvariants / monovariantsJensen / smoothing
Problem
Problem:
The following grid represents a mountain range; the number in each cell represents the height of the mountain located there. Moving from a mountain of height to a mountain of height takes time. Suppose that you start on the mountain of height and that you can move up, down, left, or right to get from one mountain to the next. What is the minimum amount of time you need to get to the mountain of height ?
| 1 | 3 | 6 | 10 | 15 | 21 | 28 |
|---|---|---|---|---|---|---|
| 2 | 5 | 9 | 14 | 20 | 27 | 34 |
| 4 | 8 | 13 | 19 | 26 | 33 | 39 |
| 7 | 12 | 18 | 25 | 32 | 38 | 43 |
| 11 | 17 | 24 | 31 | 37 | 42 | 46 |
| 16 | 23 | 30 | 36 | 41 | 45 | 48 |
| 22 | 29 | 35 | 40 | 44 | 47 | 49 |