NOJ 题目216:A problem is easy
2016-09-22 22:49
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A problem is easy
时间限制:1000ms | 内存限制:65535KB
难度:3
描述
When Teddy was a child , he was always thinking about some simple math problems ,such as “What it’s
1 cup of water plus 1 pile of dough ..” , “100 yuan buy 100 pig” .etc..
One day Teddy met a old man in his dream , in that dream the man whose name was“RuLai” gave Teddy a problem :
Given an N , can you calculate how many ways to write N as i * j + i + j (0 < i <= j) ?
Teddy found the answer when N was less than 10…but if N get bigger , he found it was too difficult for him to solve.
Well , you clever ACMers ,could you help little Teddy to solve this problem and let him have a good dream ?
输入
The first line contain a T(T <= 2000) . followed by T lines ,each line contain an integer N (0<=N <= 10^11).
输出 For each case, output the number of ways in one line
样例输入 2 1 3
样例输出 0 1
本题数学原理:由 n=i*j+i+j 推出 n+1=(i+1)*(j+1)
#include <iostream> using namespace std; int main() { int z; cin>>z; while( z-- ) { int n; cin>>n; if( n<=2 ) cout<<"0"<<endl; else { int sum=0; for( int i=1;(i+1)*(i+1)<=(n+1);i++ ) //注意!此处省略括号或者使用sqrt函数会使执行时间延长 { if( (n+1)%(i+1)==0 ) { sum++; } } cout<<sum<<endl; } } return 0; }