HDU 4747 Mex(线段树维护mex)经典

最新推荐文章于 2021-09-13 20:18:52 发布

原创

最新推荐文章于 2021-09-13 20:18:52 发布 · 1k 阅读

0 ·

CC 4.0 BY-SA版权

这是一个关于计算序列中mex值总和的问题，涉及到经典的线段树数据结构。给定一个非负整数序列，mex(L, R)表示从位置L到R（包括L和R）的连续子序列中最小的未出现非负整数。题目要求计算所有1<=L<=R<=n的情况下的mex(L, R)之和。" 52068828,5679769,C语言复习：GCC编译器、内存与变量解析,"['C语言', '编译原理', '编程基础', '内存管理']

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

Mex

Time Limit: 15000/5000 MS (Java/Others) Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 3851 Accepted Submission(s): 1278

Problem Description

Mex is a function on a set of integers, which is universally used for impartial game theorem. For a non-negative integer set S, mex(S) is defined as the least non-negative integer which is not appeared in S. Now our problem is about mex function on a sequence.

Consider a sequence of non-negative integers {ai}, we define mex(L,R) as the least non-negative integer which is not appeared in the continuous subsequence from aL to aR, inclusive. Now we want to calculate the sum of mex(L,R) for all 1 <= L <= R <= n.

Input

The input contains at most 20 test cases.
For each test case, the first line contains one integer n, denoting the length of sequence.
The next line contains n non-integers separated by space, denoting the seq