public LongNumber minus(LongNumber ln) {
if (this.sign * ln.sign < 0) {
// 異符号の場合
LongNumber lnTmp = getCloneOf(ln);
lnTmp.inverseSign();
return this.plus(lnTmp);
} else {
// 同符号の場合
// 同じ符号の引き算でケタは増えない
int newDigit = Integer.max(this.getDigit(), ln.getDigit());
LongNumber ret = getCloneOf(LongNumber.getAbsoluteMax(this, ln), newDigit);
LongNumber small = getCloneOf(LongNumber.getAbsoluteMin(this, ln), newDigit);
if (small.equals(ln)) {
ret.sign = 1;
} else {
ret.sign = -1;
}
for (int i = 0; i < newDigit; i++) {
if (ret.value[i] >= small.value[i]) {
ret.value[i] -= small.value[i];
} else {
ret.value[i + 1] -= 1;
ret.value[i] = ret.value[i] + MAX_OF_EACH_DIGIT - small.value[i];
}
}
return ret.refresh();
}
}
public LongNumber plus(LongNumber ln) {
if (this.sign * ln.sign < 0) {
// 異符号の場合
LongNumber lnNegative;
LongNumber lnPositive;
if (this.sign > 0) {
lnNegative = getCloneOf(ln);
lnPositive = getCloneOf(this);
} else {
lnNegative = getCloneOf(this);
lnPositive = getCloneOf(ln);
}
lnNegative.sign = 1;
return lnPositive.minus(lnNegative);
} else {
// 同符号の場合
// 和による繰り上がりは大きくて1桁
int newDigit = Integer.max(this.getDigit(), ln.getDigit()) + 1;
LongNumber ret = emptyLongNumber(newDigit);
ret.sign = this.sign;
for (int i = 0; i < this.getDigit(); i++) ret.value[i] += this.value[i];
for (int i = 0; i < ln.getDigit(); i++) ret.value[i] += ln.value[i];
for (int i = 0; i < newDigit - 1; i++) {
if (ret.value[i] >= MAX_OF_EACH_DIGIT) {
ret.value[i] -= MAX_OF_EACH_DIGIT;
ret.value[i + 1] += 1;
}
}
return ret.refresh();
}
}
public LongNumber multiple(LongNumber ln) {
int digit = this.getDigit() + ln.getDigit();
LongNumber ret = emptyLongNumber(digit);
ret.sign = this.sign * ln.sign;
for (int i = 0; i < this.getDigit(); i++) {
for (int j = 0; j < ln.getDigit(); j++) {
ret.value[i + j] += this.value[i] * ln.value[j];
}
}
int carry;
for (int i = 0; i < digit - 1; i++) {
carry = (int) ((double) ret.value[i] / MAX_OF_EACH_DIGIT);
ret.value[i] -= MAX_OF_EACH_DIGIT * carry;
ret.value[i + 1] += carry;
}
return ret.refresh();
}
