Square Coins

本是古典何须时尚 2022-08-07 13:44 189阅读 0赞

# Square Coins #

**Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)  
Total Submission(s): 9019    Accepted Submission(s): 6160**

Problem Description

People in Silverland use square coins. Not only they have square shapes but also their values are square numbers. Coins with values of all square numbers up to 289 (=17^2), i.e., 1-credit coins, 4-credit coins, 9-credit coins, ..., and 289-credit coins, are available in Silverland.   
There are four combinations of coins to pay ten credits:   
  
ten 1-credit coins,  
one 4-credit coin and six 1-credit coins,  
two 4-credit coins and two 1-credit coins, and  
one 9-credit coin and one 1-credit coin.   
  
Your mission is to count the number of ways to pay a given amount using coins of Silverland.

Input

The input consists of lines each containing an integer meaning an amount to be paid, followed by a line containing a zero. You may assume that all the amounts are positive and less than 300.

Output

For each of the given amount, one line containing a single integer representing the number of combinations of coins should be output. No other characters should appear in the output.

Sample Input

2
    10
    30
    0

Sample Output

1
    4
    27

母函数，这一点有点特殊，数字不连续而是指定的数字范围

#include<cstdio>
    #include<iostream>
    #include<cmath>
    using namespace std;
    int main()
    {
        int i,j,k,flag,n,a[315],b[315];
        while(cin>>n&&n)
        {
            for(i=0;i<=n;i++)
            {
                a[i]=1;
                b[i]=0;
            }
            for(i=2;i*i<=n&&i<=17;i++)
            {
                for(j=0;j<=n;j++)
                {
                    for(k=0;k+j<=n;k+=i*i)
                    {
                        b[j+k]+=a[j];
                    }
                }
                for(j=0;j<=n;j++)
                {
                    a[j]=b[j];
                    b[j]=0;
                }
            }
            printf("%d\n",a[n]);
        }
    }