求字符串编辑距离的递推和递归实现

int CalculateDis_DP(char *str1,char *str2) 
{  
	int i, j;
	int len1=strlen(str1), len2=strlen(str2);  
    
	for (i=0; i<=len2; i++)  
        d[0][i] = i;  
     
	for (i=0; i<=len1; i++)  
        d[i][0] = i;  
    
	for (i=1; i<=len1; i++)  
        for (j=1; j<=len2; j++)  
        { 
			int cost = (str1[i] == str2[j]) ? 0 : 1;    
		
			int deletion = d[i-1][j] + 1;    
			int insertion = d[i][j-1] + 1;    
			int substitution = d[i-1][j-1] + cost;    
		
			d[i][j] = min(deletion,insertion,substitution);  
        }  
	return d[len1][len2];
}

int CalculateDis_Recurse(char str1[], int astart, int aend, char str2[], int bstart, int bend)
{
	if (astart > aend)
	{
		if (bstart < bend)
			return bend-bstart+1;
		else
			return 0;
	}

	if (bstart > bend)
	{
		if (astart < aend)
			return aend-astart+1;
		else
			return 0;
	}

	if (str1[astart] == str2[bstart])
	{
		return CalculateDis_Recurse(str1, astart+1, aend, str2, bstart+1, bend);
	}

	else
	{
		int min1 = CalculateDis_Recurse(str1, astart+1, aend, str2, bstart, bend);
		int min2 = CalculateDis_Recurse(str1, astart, aend, str2, bstart+1, bend);
		int min3 = CalculateDis_Recurse(str1, astart+1, aend, str2, bstart+1, bend);
		return min(min1,min2,min3)+1;
	}
}