POJ-1579-Function Run Fun

比较水的DP题，按照题目要求做即可

代码：

#include<cstdio>#include<cstring>#include<iostream>using namespace std;int dp[21][21][21];int Init(){    for(int i=0;i<=20;i++)for(int j=0;j<=20;j++)    for(int k=0;k<=20;k++)    {if(i<=0||j<=0||k<=0)    dp[i][j][k]=1;else if(i<j&&j<k)    dp[i][j][k]=dp[i][j][k-1]+dp[i][j-1][k-1]-dp[i][j-1][k];else    dp[i][j][k]=dp[i-1][j][k]+dp[i-1][j-1][k]+dp[i-1][j][k-1]-dp[i-1][j-1][k-1];    }}int main(){    int a,b,c;    Init();    while(scanf("%d%d%d",&a,&b,&c)!=EOF)    {if(a==-1&&b==-1&&c==-1)    break;if(a<=0||b<=0||c<=0)    printf("w(%d, %d, %d) = %d\n",a,b,c,dp[0][0][0]);else if(a>20||b>20||c>20)    printf("w(%d, %d, %d) = %d\n",a,b,c,dp[20][20][20]);else    printf("w(%d, %d, %d) = %d\n",a,b,c,dp[a][b][c]);    }    return 0;}