HMMT 二月 2001 · 冲刺赛 · 第 29 题
HMMT February 2001 — Guts Round — Problem 29
题目详情
英文原题
- [10] Count the number of sequences a , a , a , a , a of integers such that a ≤ 1 for
1 2 3 4 5 iall i and all partial sums ( a , a + a , etc.) are non-negative.
1 1 2 2
解析
英文解析
- [10] Count the number of sequences a , a , a , a , a of integers such that a ≤ 1 for
1 2 3 4 5 iall i and all partial sums ( a , a + a , etc.) are non-negative.
1 1 2
Solution: C (length + 1) = C (6) = 132 . 2