ACM学习历程——HDU1331 Function Run Fun（锻炼多维dp的打表）

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <set>
#include <map>
#include <vector>
#include <queue>
#include <string>
#define inf 0x3fffffff
#define eps 1e-10

using namespace std;

int f[25][25][25];

void Init()
{
    for (int i = 0; i <= 20; i++)
        for (int j = 0; j <= 20; j++)
            f[i][j][0] = f[i][0][j] = f[0][i][j] = 1;
    for (int i = 1; i <= 20; i++)
        for (int j = 1; j <= 20; j++)
            for (int k = 1; k <= 20; k++)
            {
                if (i < j && j < k)
                    f[i][j][k] = f[i][j][k-1] + f[i][j-1][k-1] - f[i][j-1][k];
                else
                    f[i][j][k] = f[i-1][j][k] + f[i-1][j-1][k] + f[i-1][j][k-1] - f[i-1][j-1][k-1];
            }
}

int w(int a, int b, int c)
{
    if (a <= 0 || b <= 0 || c <= 0)
        return 1;
    if (a > 20 || b > 20 || c > 20)
        return f[20][20][20];
    return f[a][b][c];
}

int main()
{
    //freopen("test.txt", "r", stdin);
    Init();
    int a, b, c;
    while (scanf("%d%d%d", &a, &b, &c) != EOF)
    {
        if (a == -1 && b == -1 && c == -1)
            break;
        printf("w(%d, %d, %d) = ", a, b, c);
        printf("%d\n", w(a, b, c));
    }
    return 0;
}