Hdu-1331-function Run Fun (Dynamic planning 3)

Description

We all love recursion! Don ' t we?

Consider a three-parameter recursive function w (A, B, c):

If a <= 0 or b <= 0 or C <= 0, then W (A, B, c) returns:
1

If a > B > or C >, then W (A, B, c) returns:
W (20, 20, 20)

If a < b and B < C, then W (A, B, c) returns:
W (A, B, c-1) + W (A, b-1, C-1)-W (A, b-1, c)

Otherwise it returns:
W (A-1, B, c) + W (A-1, B-1, C) + W (A-1, B, C-1)-W (A-1, B-1, C-1)

This is a easy function to implement. The problem is, if implemented directly, for moderate values of a, B and C (for example, a = d, B = d, c = All), the prog Ram takes hours to run because of the massive recursion.

Input

The input for your program would be a series of an integer triples, one per line, until the END-OF-FILE flag of-1-1-1. Using The above technique, you is to calculate W (A, B, c) efficiently and print the result.

Output

Print the value for W (a,b,c) for each triple.

Sample Input

1 1 12 2 210 4 650 50 50-1 7 18-1-1-1

Sample Output

W (1, 1, 1) = 2w (2, 2, 2) = 4w (Ten, 4, 6) = 523w (-1, 7, 18) = 1

Similar to the dynamic planning, to avoid duplication of calculations, the previous count of the array to save, directly behind the use of it can be

#include <stdio.h>#include<string.h>inta,b,c;intans[ +][ +][ +];intWintAintBintc) {    if(a<=0|| b<=0|| c<=0)    {        return 1; }    if(a> -|| B> -|| C> -)    {        returnW -, -, -); }    if(Ans[a][b][c])returnAns[a][b][c]; if(a<b&&b<c) {Ans[a][b][c]=w (a,b,c-1) +w (a,b-1, C-1)-W (a,b-1, c); }    Else{Ans[a][b][c]=w (A-1, B,c) + W (A-1, B-1, c) + W (A-1, b,c-1)-W (A-1, B-1, C-1); }    returnans[a][b][c];}intMain () { while(SCANF ("%d%d%d", &a,&b,&c) &&a+b+c!=-3) {memset (ans,0,sizeof(ans));        W (A,B,C); printf ("W (%d,%d,%d) =%d\n", A,b,c,w (a,b,c)); }    return 0;}

Hdu-1331-function Run Fun (Dynamic planning 3)