hdu 1709 普通母函数

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这道题与别的母函数题不一样，利用了天平的原理，一开始只是盲目的套一下模版，但后来发现他们的重量不只是相加，也可以相减，但是我只是写出了一种相减的情况，就是利用的得出的重量减去第i种的重量，且没有写到第i种的重量减去得出的重量。。如果不懂可以看一下代码。

#include <iostream>#include <cstring>#include <vector>using namespace std;int n;int sum;int c1[11000],c2[11000];int w[110];void init(){    sum=0;    for(int i=1;i<=n;++i)    {        cin>>w[i];        sum+=w[i];    }}void solve(){    memset(c1,0,sizeof(c1));    memset(c2,0,sizeof(c2));    c1[w[1]]=1;c1[0]=1;    for(int cnt=2;cnt<=n;++cnt)    {        int i=w[cnt];        for(int j=0;j<=sum;++j)        {            if(c1[j])            {                for(int k=0;k<=i;k+=i)                {                    if(k+j<=sum)                        c2[k+j]+=c1[j];                    if(j-k>0)                        c2[j-k]+=c1[j];                    if(k>j)                        ++c2[k-j];                }            }        }        memcpy(&c1,&c2,sizeof(c2));        memset(c2,0,sizeof(c2));    }    vector<int> v;int num=0;    for(int i=1;i<=sum;++i)    {        if(!c1[i])        {            ++num;            v.push_back(i);        }    }    cout<<num<<endl;    if(num)    {        for(int i=0;i<num-1;++i)            cout<<v[i]<<" ";        cout<<v[num-1]<<endl;    }}int main(int argc, const char * argv[]){    while(cin>>n)    {        init();        solve();    }    return 0;}//4//1 3 5 8//answer:0

The Balance

Time Limit: 1000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7623 Accepted Submission(s): 3167

Problem Description

Now you are asked to measure a dose of medicine with a balance and a number of weights. Certainly it is not always achievable. So you should find out the qualities which cannot be measured from the range [1,S]. S is the total quality of all the weights.

Input

The input consists of multiple test cases, and each case begins with a single positive integer N (1<=N<=100) on a line by itself indicating the number of weights you have. Followed by N integers Ai (1<=i<=N), indicating the quality of each weight where 1<=Ai<=100.

Output

For each input set, you should first print a line specifying the number of qualities which cannot be measured. Then print another line which consists all the irrealizable qualities if the number is not zero.

Sample Input

31 2 439 2 1

Sample Output

024 5

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