2013暑假集训B组训练赛第二场 - B - Funky Numbers

最新推荐文章于 2022-03-24 22:46:23 发布

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最新推荐文章于 2022-03-24 22:46:23 发布

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原文链接：http://www.cnblogs.com/wejex/p/3219485.html

本文介绍了一个算法问题：如何判断一个给定的整数是否可以表示为两个三角形数的和。通过使用C++编程语言，文章详细展示了如何生成一系列三角形数并检查目标数字是否能由这些三角形数的组合来表示。

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B - Funky Numbers

Time Limit:2000MS Memory Limit:262144KB 64bit IO Format:%I64d & %I64u

Submit Status Practice CodeForces 192A

Description

As you very well know, this year's funkiest numbers are so called triangular numbers (that is, integers that are representable as $\text{[math]}$ , where k is some positive integer), and the coolest numbers are those that are representable as a sum of two triangular numbers.

A well-known hipster Andrew adores everything funky and cool but unfortunately, he isn't good at maths. Given number n, help him define whether this number can be represented by a sum of two triangular numbers (not necessarily different)!

Input

The first input line contains an integer n (1 ≤ n ≤ 10⁹).

Output

Print "YES" (without the quotes), if n can be represented as a sum of two triangular numbers, otherwise print "NO" (without the quotes).

Sample Input

Input

Output

YES

Input

Output

NO


一开始开了个10^9的数组，结果mle
后来改了还是tle
然后继续怎么都过不了
然后一把乱改，结果改好了。。。= =
心酸；

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

const long long MAXN = 1000000005;

int num;
int f[50000];
int n;

void build()
{
    n = 0;
    int k;
    for(int i = 1; k < MAXN; i++)
    {
        k = i*(i+1)/2;
        f[n++]= k;
    }
}


int main()
{
    build();
    n--;
    while(~scanf("%d",&num))
    {
        bool is = 0;
        for(int i = 0; f[i] < num; i++)
        {
            int id = lower_bound(f, f + n,num - f[i]) - f;

            if(f[id] == num - f[i])
            {
                is = true;
                break;
            }
        }
        printf("%s\n", is ? "YES" : "NO");
    }
    return 0;
}

转载于:https://www.cnblogs.com/wejex/p/3219485.html