ACM PKU 1579 Function Run Fun http://acm.pku.edu.cn/JudgeOnline/problem?id=1579

连我就能十分钟以内搞定的代码还有什么好说的呢！

提醒一下，用递归是多么愚蠢，用记忆搜索才是王道，还有注意格式，最好直接粘原题！！！

#include <iostream>
using namespace std;
int max = 21;
int sign[21][21][21];
void init()
{
int i, j, k;
    sign[0][0][0] = 1;
for (i = 0;i < 21; i++ )
for (j = 0;j < 21; j++ )
{
sign[0][i][j] = 1;
sign[i][0][j] = 1;
sign[i][j][0] = 1;

} 
for (i = 1;i < 21; i++ )
for (j = 1;j < 21; j++ )
for (k = 1;k < 21; k++ )
{
if (i < j && j < k) sign[i][j][k] = sign[i][ j][k-1] + sign[i][j-1][k-1] - sign[i][j-1][k] ;
else sign[i][j][k] = sign[i-1][j][k] + sign[i-1][j-1][k] + sign[i-1][j][k-1] - sign[i-1][j-1][k-1];
}
}
int main ()
{
init();
int a,b,c;
while (cin>> a >> b>> c)
{
if (a == -1 && b == -1 && c == -1)
break;
if ( a < 0 || b < 0 || c < 0 ) 
{
cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<sign[0][0][0]<<endl;
continue;
};
if (a > 20 || b > 20 || c > 20)
            cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<sign[20][20][20]<<endl;
else 
cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<sign[a][b][c]<<endl;

}
return 0;
}