zoukankan      html  css  js  c++  java
  • (数论)LightOJ -- 1245

    http://acm.hust.edu.cn/vjudge/contest/view.action?cid=98634#problem/B(acm14)

    Description

    I was trying to solve problem '1234 - Harmonic Number', I wrote the following code

    long long H( int n ) {
        long long res = 0;
        for( int i = 1; i <= n; i++ )
            res = res + n / i;
        return res;
    }

    Yes, my error was that I was using the integer divisions only. However, you are given n, you have to find H(n) as in my code.

    Input

    Input starts with an integer T (≤ 1000), denoting the number of test cases.

    Each case starts with a line containing an integer n (1 ≤ n < 231).

    Output

    For each case, print the case number and H(n) calculated by the code.

    Sample Input

    11

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    2147483647

    Sample Output

    Case 1: 1

    Case 2: 3

    Case 3: 5

    Case 4: 8

    Case 5: 10

    Case 6: 14

    Case 7: 16

    Case 8: 20

    Case 9: 23

    Case 10: 27

    Case 11: 46475828386

    #include <iostream>
    #include <cstdio>
    #include <cstring>
    #include <cstdlib>
    #include <cmath>
    #include <algorithm>
    #include <map>
    
    using namespace std;
    
    #define N 200005
    
    int main()
    {
        long long T, iCase=1;
    
        scanf("%d", &T);
    
        while(T--)
        {
            long long n, i;
    
            scanf("%lld", &n);
    
    
            long long a, num = 1, sum = n, pre=n;
    
            for(i=2; i<=n; i++)
            {
                a = n/i;
                num += (pre-a);
                sum += (pre-a)*(i-1);
    
                if(num==n)
                    break;
    
                num++;
                sum += a;
                if(num==n)
                    break;
    
                pre = a;
            }
    
            printf("Case %lld: %lld
    ", iCase++, sum);
        }
    
        return 0;
    }
    勿忘初心
  • 相关阅读:
    设计模式六大原则
    .net Stream篇(七)
    .net Stream篇(六)
    .net Stream篇(五)
    .net Stream篇(四)
    Leetcode 18
    Leetcode 16
    Leetcode 15
    Leetcode 12
    Leetcode 9
  • 原文地址:https://www.cnblogs.com/YY56/p/4947483.html
Copyright © 2011-2022 走看看