zoukankan      html  css  js  c++  java
  • HDU 5122 K.Bro Sorting

    K.Bro Sorting
    Time Limit: 2000/2000 MS (Java/Others) Memory Limit: 512000/512000 K (Java/Others)
    Total Submission(s): 2510 Accepted Submission(s): 1174


    Problem Description Matt’s friend K.Bro is an ACMer.

    Yesterday, K.Bro learnt an algorithm: Bubble sort. Bubble sort will compare each pair of adjacent items and swap them if they are in the wrong order. The process repeats until no swap is needed.

    Today, K.Bro comes up with a new algorithm and names it K.Bro Sorting.

    There are many rounds in K.Bro Sorting. For each round, K.Bro chooses a number, and keeps swapping it with its next number while the next number is less than it. For example, if the sequence is “1 4 3 2 5”, and K.Bro chooses “4”, he will get “1 3 2 4 5” after this round. K.Bro Sorting is similar to Bubble sort, but it’s a randomized algorithm because K.Bro will choose a random number at the beginning of each round. K.Bro wants to know that, for a given sequence, how many rounds are needed to sort this sequence in the best situation. In other words, you should answer the minimal number of rounds needed to sort the sequence into ascending order. To simplify the problem, K.Bro promises that the sequence is a permutation of 1, 2, . . . , N .


    Input The first line contains only one integer T (T ≤ 200), which indicates the number of test cases. For each test case, the first line contains an integer N (1 ≤ N ≤ 106).

    The second line contains N integers ai (1 ≤ ai ≤ N ), denoting the sequence K.Bro gives you.

    The sum of N in all test cases would not exceed 3 × 106.


    Output For each test case, output a single line “Case #x: y”, where x is the case number (starting from 1), y is the minimal number of rounds needed to sort the sequence.
    Sample Input

    2
    5
    5 4 3 2 1
    5
    5 1 2 3 4


    Sample Output

    Case #1: 4
    Case #2: 1


    Hint
    In the second sample, we choose “5” so that after the first round, sequence becomes “1 2 3 4 5”, and the algorithm completes.


    Source 2014ACM/ICPC亚洲区北京站-重现赛(感谢北师和上交)
    解析:只要一个数后面有比它小的数,至少会进行一轮交换。因为可以任意选择开始的位置,我们每次选择未排序序列中最大的那个数开始,可以得到最少的次数。
    ``` #include

    const int MAXN = 1e6+5;
    int n;
    int a[MAXN];

    void solve()
    {
    int res = 0;
    int m = a[n];
    for(int i = n-1; i >= 1; --i){
    if(a[i] > m)
    ++res;
    else
    m = a[i];
    }
    printf("%d ", res);
    }

    int main()
    {
    int t, cn = 0;
    scanf("%d", &t);
    while(t--){
    scanf("%d", &n);
    for(int i = 1; i <= n; ++i)
    scanf("%d", &a[i]);
    printf("Case #%d: ", ++cn);
    solve();
    }
    return 0;
    }

  • 相关阅读:
    Pandas: 如何将一列中的文本拆分为多行? | Python
    Python项目实战:福布斯系列之数据采集
    Python: Pandas运算的效率探讨以及如何选择高效的运算方式
    Pandas数据处理实战:福布斯全球上市企业排行榜数据整理
    从历史来看印度的裂痕和隐忧 | 阅览群书
    Python库:序列化和反序列化模块pickle介绍
    无法加载 DLL“SQLite.Interop.DLL”: 找不到指定的模块。 (异常来自 HRESULT:0x8007007E)。
    spring 问题笔记
    java 大量数据处理问题记录
    spring mvc 整合swagger
  • 原文地址:https://www.cnblogs.com/inmoonlight/p/5990820.html
Copyright © 2011-2022 走看看