Square Country
Time limit: 1.0 second
Memory limit: 64 MB
There live square people in a square country. Everything in this country is square also. Thus, the Square Parliament has passed a law about a land. According to the law each citizen of the country has a right to buy land. A land is sold in squares, surely. Moreover, a length of a square side must be a positive integer amount of meters. Buying a square of land with a side a one pays a 2 quadrics (a local currency) and gets a square certificate of a landowner. One citizen of the country has decided to invest all of his N quadrics into the land. He can, surely, do it, buying square pieces 1 × 1 meters. At the same time the citizen has requested to minimize an amount of pieces he buys: "It will be easier for me to pay taxes," — he has said. He has bought the land successfully. Your task is to find out a number of certificates he has gotten.
Input
The only line contains a positive integer N ≤ 60 000 , that is a number of quadrics that the citizen has invested.
Output
The only line contains a number of certificates that he has gotten.
Sample
input | output |
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| |
/**
就是求一個數最少等于幾個平方數的和~~~不知道定理的人一般就當背包做了,那樣一定逾時= =!
~~~~~四平方和定理~~~~~
見連結:
http://zh.wikipedia.org/wiki/%E5%9B%9B%E5%B9%B3%E6%96%B9%E5%92%8C%E5%AE%9A%E7%90%86
**/
#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
#define maxn 61006
int value(int n)/**四平方和定理(因為在dp分組裡找到了這道題,是以自然認為是dp題,不該啊~~~~)**/
{
int i,j,k;
int data;
if(n==1)
return 1;
data=sqrt(n);
for(i=0; i<=data; i++)
if(n==i*i)
return 1;
for(i=0; i<=data; i++)
for(j=i; j<=data; j++)
if(n==i*i+j*j)
return 2;
for(i=0; i<=data; i++)
for(j=i; j<=data; j++)
for(k=j; k<=data; k++)
if(n==i*i+j*j+k*k)
return 3;
return 4;
}
void read()
{
int n;
scanf("%d",&n);
printf("%d\n",value(n));
}
int main()
{
read();
return 0;
}