动态规划 矩阵链

/*************************************************************************
    > File Name: maxtrix_chain.c
    > Author: He Xingjie
    > Mail: gxmshxj@163.com
    > Created Time: 2014年05月18日 星期日 11时31分33秒
    > Description:动态规划求矩阵链乘法的乘数最小 
 ************************************************************************/
#include<stdio.h>

#define MAX 50

typedef struct{
    int a;
    int b;
}Matrix;

Matrix matrix[MAX];
int m[MAX][MAX];
int s[MAX][MAX];

void Input(int *len)
{
    int i;
    FILE *filp;

    filp = fopen("in.txt","r");
    if (filp == NULL)
        printf("file ope failed!\n");
    fscanf(filp, "%d", len);    
    /*scanf("%d", len);*/

    for(i = 0; i < *len; i++)
    {
        /*scanf("%d%d", &matrix[i].a, &matrix[i].b);*/
        fscanf(filp, "%d%d", &matrix[i].a, &matrix[i].b);
    }
}

int MatrixChain(int len)
{
    int l, i, j, k;
    int tmp;

    for (i = 0; i < len; i++)
    {
        for (j = i; j < len; j++)
        {
            if (i == j)
                m[i][i] = 0;
            else
                m[i][j] = 99999999;

            s[i][j] = 0;
        }
    }

    for (l = 2; l <= len; l++)
    {
        for (i = 0; i < len-l+1; i++)
        {
            j = i+l-1;
            for (k = i; k < j; k++)
            {
                tmp = m[i][k] + m[k+1][j] +
                    matrix[i].a * matrix[k].b * matrix[j].b;
                if (tmp < m[i][j])
                {
                    m[i][j] = tmp;
                    s[i][j] = k;
                }
            }
        }
    }
    
    return m[0][len-1];
    
}

void PrintResult(int i, int j)
{
    if (i == j)
        printf("A%d", i);
    else
    {
        printf("(");
        PrintResult(i, s[i][j]);
        PrintResult(s[i][j]+1, j);
        printf(")");
    }
}

void PrintM(int len)
{
    int i, j;
    for (i = 0; i < len; i++)
    {
        for (j = 0; j < len; j++)
        {
            printf("%d ",m[i][j]);
        }
        printf("\n");
    }
}

int main(void)
{
    int n, ret;
    Input(&n);
    printf("n:%d\n", n);

    ret = MatrixChain(n); 
    printf("result:%d\n", ret);
    printf("k:%d.\n", s[0][n-1]);
    PrintM(n);
    PrintResult(0, n-1);
    return 0;
}