POJ 1579 Function Run Fun

方程都给出来了，直接敲代码就好了。

#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;int dp[25][25][25];int dfs(int a,int b,int c){    if(a<=0 || b<=0 || c<=0)        return 1;    if(a>20 || b>20 || c>20)        return dfs(20,20,20);    if(dp[a][b][c])        return dp[a][b][c];    if(a<b && b<c)        dp[a][b][c] = dfs(a,b,c-1)+dfs(a,b-1,c-1)-dfs(a,b-1,c);    else        dp[a][b][c] = dfs(a-1,b,c)+dfs(a-1,b-1,c)+dfs(a-1,b,c-1)-dfs(a-1,b-1,c-1);    return dp[a][b][c];}int main(){    int a,b,c;    memset(dp,0,sizeof(dp));    while(~scanf("%d%d%d",&a,&b,&c))    {        if(a == -1 && b == -1 && c == -1)            break;        printf("w(%d, %d, %d) = %d\n",a,b,c,dfs(a,b,c));    }    return 0;}