暴力模拟多种情况。我是用搜索写的，注意返回条件和约束条件。

#include
     
      #include
      
       #include
       
        #include
        
         #include
         
          using namespace std;int a,b,c;int ans[1000],l;bool f[50][50][50];void dfs(int x,int y,int z){    if(f[x][y][z]) return;    if(x==0) ans[++l]=z;    f[x][y][z]=1;    dfs(x-min(x,b-y),y+min(x,b-y),z);    dfs(x+min(y,a-x),y-min(y,a-x),z);    dfs(x+min(z,a-x),y,z-min(z,a-x));    dfs(x-min(x,c-z),y,z+min(x,c-z));    dfs(x,y-min(y,c-z),z+min(y,c-z));    dfs(x,y+min(z,b-y),z-min(z,b-y));    return;}int main(){    scanf("%d%d%d",&a,&b,&c);    dfs(0,0,c);    sort(ans+1,ans+l+1);    for(int i=1;i<=l;i++)      printf("%d ",ans[i]);    return 0;}