用java实现乘法算法
我尝试使用Java实现以下乘法算法: m:数字是多少 n:是b的位数 β:是基础吗 这是实现此算法的java函数:用java实现乘法算法,java,algorithm,biginteger,multiplication,Java,Algorithm,Biginteger,Multiplication,我尝试使用Java实现以下乘法算法: m:数字是多少 n:是b的位数 β:是基础吗 这是实现此算法的java函数: public BigInteger prodbigbig(BigInteger a, BigInteger b, Integer base ){ ArrayList<Integer> listA = new ArrayList<Integer>(); ArrayList<Integer> listB = ne
public BigInteger prodbigbig(BigInteger a, BigInteger b, Integer base ){
ArrayList<Integer> listA = new ArrayList<Integer>();
ArrayList<Integer> listB = new ArrayList<Integer>();
ArrayList<Integer> listC = new ArrayList<Integer>();
int m = a.toString().length();
int n = b.toString().length();
Integer carry, temp;
BigInteger result = BigInteger.ZERO;
for(int i = 0; i < a.toString().length(); i++){
listA.add(Character.getNumericValue( a.toString().charAt(i)));
}
for(int i = 0; i < b.toString().length(); i++){
listB.add((Character.getNumericValue( b.toString().charAt(i))));
}
for(int i= 0; i <= m - 1; i++){
listC.add(0);
}
for(int k = 0; k <= n - 1 ; k++) {
carry = 0;
for(int i = 0; i <= m - 1; i++){
temp = (listA.get(i) * listB.get(k)) + listC.get(i + k) + carry;
listC.add(i+k,temp % base);
carry = temp / base;
}
listC.add(k + m,carry);
}
for(int i = 0; i < m + n; i++) {
result = result.add(BigInteger.valueOf((long) (listC.get(i)*(Math.pow(base, i)))));
}
return result;
}
public biginger prodbigbig(biginger a、biginger b、整数基){
ArrayList listA=新的ArrayList();
ArrayList listB=新的ArrayList();
ArrayList listC=新的ArrayList();
int m=a.toString().length();
int n=b.toString().length();
整数进位,温度;
BigInteger结果=BigInteger.0;
for(int i=0;i
listC.set(i+k,temp % base);
最后一次到BigInteger的转换将溢出足够大的数字。我将完全去掉ArrayList
,使用int
数组,然后在最后将其转换为byte[]
,并将其直接提供给BigInteger的构造函数。
那应该是
listC.set(i+k,temp % base);
最后一次到BigInteger的转换将溢出足够大的数字。我将完全去掉ArrayList
,使用int
数组,然后将其转换为byte[]
结尾,并将其直接输入到biginger的构造函数。
看起来您应该使用set
而不是在listC中使用add
,因为add(index,value),在index之后移动其他元素,但是set
被替换
public BigInteger prodbigbig(BigInteger a, BigInteger b, Integer base ){
ArrayList<Integer> listA = new ArrayList<Integer>();
ArrayList<Integer> listB = new ArrayList<Integer>();
ArrayList<Integer> listC = new ArrayList<Integer>();
int m = a.toString().length();
int n = b.toString().length();
Integer carry, temp;
BigInteger result = BigInteger.ZERO;
for(int i = 0; i < a.toString().length(); i++){
listA.add(Character.getNumericValue( a.toString().charAt(i)));
}
for(int i = 0; i < b.toString().length(); i++){
listB.add((Character.getNumericValue( b.toString().charAt(i))));
}
for(int i= 0; i <= m - 1; i++){
listC.add(0);
}
for(int k = 0; k <= n - 1 ; k++) {
carry = 0;
for(int i = 0; i <= m - 1; i++){
temp = (listA.get(i) * listB.get(k)) + listC.get(i + k) + carry;
listC.set(i+k,temp % base);
carry = temp / base;
}
listC.set(k + m,carry);
}
for(int i = 0; i < m + n; i++) {
result = result.add(BigInteger.valueOf((long) (listC.get(i)*(Math.pow(base, i)))));
}
return result;
}
public biginger prodbigbig(biginger a、biginger b、整数基){
ArrayList listA=新的ArrayList();
ArrayList listB=新的ArrayList();
ArrayList listC=新的ArrayList();
int m=a.toString().length();
int n=b.toString().length();
整数进位,温度;
BigInteger结果=BigInteger.0;
for(int i=0;i 对于(int i=0;i看起来应该在listC中使用set
而不是add
,因为add(index,value)在index之后移动其他元素,但是set
被替换
public BigInteger prodbigbig(BigInteger a, BigInteger b, Integer base ){
ArrayList<Integer> listA = new ArrayList<Integer>();
ArrayList<Integer> listB = new ArrayList<Integer>();
ArrayList<Integer> listC = new ArrayList<Integer>();
int m = a.toString().length();
int n = b.toString().length();
Integer carry, temp;
BigInteger result = BigInteger.ZERO;
for(int i = 0; i < a.toString().length(); i++){
listA.add(Character.getNumericValue( a.toString().charAt(i)));
}
for(int i = 0; i < b.toString().length(); i++){
listB.add((Character.getNumericValue( b.toString().charAt(i))));
}
for(int i= 0; i <= m - 1; i++){
listC.add(0);
}
for(int k = 0; k <= n - 1 ; k++) {
carry = 0;
for(int i = 0; i <= m - 1; i++){
temp = (listA.get(i) * listB.get(k)) + listC.get(i + k) + carry;
listC.set(i+k,temp % base);
carry = temp / base;
}
listC.set(k + m,carry);
}
for(int i = 0; i < m + n; i++) {
result = result.add(BigInteger.valueOf((long) (listC.get(i)*(Math.pow(base, i)))));
}
return result;
}
public biginger prodbigbig(biginger a、biginger b、整数基){
ArrayList listA=新的ArrayList();
ArrayList listB=新的ArrayList();
ArrayList listC=新的ArrayList();
int m=a.toString().length();
int n=b.toString().length();
整数进位,温度;
BigInteger结果=BigInteger.0;
for(int i=0;i 对于(int i=0;i我通过以下方式解决了修改代码的问题:
public BigInteger prodBigBig(BigInteger a, BigInteger b, int base ){
BigInteger result = BigInteger.ZERO;
if(a.compareTo(result) == 0 || b.compareTo(result) == 0)
return result;
int m = a.toString().length();
int n = b.toString().length();
int carry;
int temp;
ArrayList<Integer>listA = new ArrayList<>();
ArrayList<Integer>listB = new ArrayList<>();
int[] listC = new int[m + n];
for(int i = m - 1; i >= 0; i--){
listA.add(Character.getNumericValue( a.toString().charAt(i)));
listC[i] = 0;
}
for(int i = n - 1; i >= 0; i--) {
listB.add(Character.getNumericValue(b.toString().charAt(i)));
}
for(int k=0; k < n; k++) {
carry = 0;
for(int i = 0; i < m ; i++){
temp = (listA.get(i) * listB.get(k)) + listC[i + k] + carry;
listC[i + k] = temp % base;
carry = temp / base;
}
listC[k + m] = carry;
}
for(int i= 0; i < m + n; i++){
result = result.add(BigInteger.valueOf((long) (listC[i] * Math.pow(base, i))));
}
return result;
}
public biginger prodBigBig(biginger a,biginger b,int base){
BigInteger结果=BigInteger.0;
如果(a.compareTo(结果)==0 | | b.compareTo(结果)==0)
返回结果;
int m=a.toString().length();
int n=b.toString().length();
整数进位;
内部温度;
ArrayListA=新的ArrayList();
ArrayListB=新的ArrayList();
int[]listC=新的int[m+n];
对于(int i=m-1;i>=0;i--){
add(Character.getNumericValue(a.toString().charAt(i));
listC[i]=0;
}
对于(int i=n-1;i>=0;i--){
add(Character.getNumericValue(b.toString().charAt(i));
}
对于(int k=0;k
我通过以下方式解决了修改代码的问题:
public BigInteger prodBigBig(BigInteger a, BigInteger b, int base ){
BigInteger result = BigInteger.ZERO;
if(a.compareTo(result) == 0 || b.compareTo(result) == 0)
return result;
int m = a.toString().length();
int n = b.toString().length();
int carry;
int temp;
ArrayList<Integer>listA = new ArrayList<>();
ArrayList<Integer>listB = new ArrayList<>();
int[] listC = new int[m + n];
for(int i = m - 1; i >= 0; i--){
listA.add(Character.getNumericValue( a.toString().charAt(i)));
listC[i] = 0;
}
for(int i = n - 1; i >= 0; i--) {
listB.add(Character.getNumericValue(b.toString().charAt(i)));
}
for(int k=0; k < n; k++) {
carry = 0;
for(int i = 0; i < m ; i++){
temp = (listA.get(i) * listB.get(k)) + listC[i + k] + carry;
listC[i + k] = temp % base;
carry = temp / base;
}
listC[k + m] = carry;
}
for(int i= 0; i < m + n; i++){
result = result.add(BigInteger.valueOf((long) (listC[i] * Math.pow(base, i))));
}
return result;
}
public biginger prodBigBig(biginger a,biginger b,int base){
BigInteger结果=BigInteger.0;
如果(a.compareTo(结果)==0 | | b.compareTo(结果)==0)
返回结果;
int m=a.toString().length();
int n=b.toString().length();
整数进位;
内部温度;
ArrayListA=新的ArrayList();
ArrayListB=新的ArrayList();
int[]listC=新的int[m+n];
对于(int i=m-1;i>=0;i--){
add(Character.getNumericValue(a.toString().charAt(i));
listC[i]=0;
}
对于(int i=n-1;i>=0;i--){
add(Character.getNumericValue(b.toString().charAt(i));
}
对于(int k=0;k