go-leetcode/multiply_strings/multiply_strings.go at master · hitzzc/go-leetcode · GitHub

Name: go-leetcode/multiply_strings/multiply_strings.go at master · hitzzc/go-leetcode · GitHub
Rating: 4.9 (8772 reviews)
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package multiply_strings

funcmultiply(num1string, num2string) string {
num1Bytes, num2Bytes:= []byte(num1), []byte(num2)
num1Ints, num2Ints:=BytesToInts(num1Bytes), BytesToInts(num2Bytes)
varret []int
fori:=0; i<len(num2Ints); i++ {
tmp:=oneMultiply(num1Ints, num2Ints[i])
ret=intsPlus(append(ret, 0), tmp)
 }
iflen(ret) ==0 {
return"0"
 }
variint
fori=rangeret {
ifret[i] !=0 {
break
 }
 }
ret=ret[i:]
returnstring(IntsToBytes(ret))
}

funcBytesToInts(bytes []byte) (ints []int) {
ints=make([]int, len(bytes))
fori, b:=rangebytes {
ints[i] =int(b-'0')
 }
return
}

funcIntsToBytes(ints []int) (bytes []byte) {
iflen(ints) ==0 {
return []byte{'0'}
 }
m:= []byte("0123456789")
bytes=make([]byte, len(ints))
fori, val:=rangeints {
bytes[i] =m[val]
 }
return
}

funconeMultiply(num1 []int, num2int) []int {
carry:=0
ret:=make([]int, len(num1)+1)
fori:=len(num1) -1; i>=0; i-- {
dot:=num1[i]*num2+carry
ifdot>9 {
carry=dot/10
dot=dot%10
 } else {
carry=0
 }
ret[i+1] =dot
 }
ifcarry==0 {
returnret[1:]
 }
ret[0] =carry
returnret
}

funcintsPlus(num1, num2 []int) []int {
iflen(num1) ==0 {
returnnum2
 }
iflen(num2) ==0 {
returnnum1
 }
varshort, long []int
iflen(num1) <len(num2) {
short=num1
long=num2
 } else {
short=num2
long=num1
 }
newShort:=make([]int, len(long)-len(short))
newShort=append(newShort, short...)
ret:=make([]int, len(long)+1)
carry:=0
fori:=len(newShort) -1; i>=0; i-- {
sum:=carry+newShort[i] +long[i]
ifsum>9 {
carry=sum/10
sum=sum%10
 } else {
carry=0
 }
ret[i+1] =sum
 }
ifcarry==0 {
returnret[1:]
 }
ret[0] =carry
returnret
}