HDU 2058 The Sum Problem

Posted 2020-12-25 zlrrrr

http://acm.hdu.edu.cn/showproblem.php?pid=2058

 

Problem Description

Given a sequence 1,2,3,......N, your job is to calculate all the possible sub-sequences that the sum of the sub-sequence is M.

 

Input

Input contains multiple test cases. each case contains two integers N, M( 1 <= N, M <= 1000000000).input ends with N = M = 0.

 

Output

For each test case, print all the possible sub-sequence that its sum is M.The format is show in the sample below.print a blank line after each test case.

 

Sample Input

20 10

50 30

0 0

 

Sample Output

[1,4]

[10,10]

 

[4,8]

[6,9]

[9,11]

[30,30]

 

代码：

#include <bits/stdc++.h>
using namespace std;

int n,m;

int main() {
    while(~scanf("%d%d", &n, &m)) {
            if( n == 0 && m == 0) break;
       for(int i = sqrt(2 * m); i >= 1; i --) {
            int a = (m - ((i - 1) * i) / 2) / i;
            if(m == a * i + (i * (i - 1)) / 2)
            cout<< ‘[‘ << a << ‘,‘ << a + i - 1 << ‘]‘ <<endl;
        }
        printf("
");
    }
    return 0;
}