不過還是寫的很醜
sign
Add Binary
class Solution {
public:
string addBinary(string a, string b) {
int lenA = a.length();
int lenB = b.length();
string ret;
int i,j, flag = 0;
for(i=lenA,j=lenB;(i>0 || j>0);i--,j--)
{
int anum = 0,bnum = 0;
if (i>0)
anum = a[i -1] - '0';
if (j>0)
bnum = b[j -1] - '0';
int tmp = flag + anum + bnum;
if (tmp > 1)
{
flag = 1;
tmp -=2;
}
else
flag = 0;
ret = to_string(tmp) + ret;
}
if (flag>0)
ret = "1" + ret;
return ret;
}
};
[20260710] 更新
奇怪別人寫就是比較漂亮 ～—～
#define max(a,b) (a>b)?(a):(b)
void reverse(char *a, char *b){
char tmp = *a;
*a=*b;
*b=tmp;
}
char* addBinary(char* a, char* b) {
int l1 = strlen(a);
int l2 = strlen(b);
int longer= max(l1, l2);
int carry = 0;
char *ret = calloc(longer+2, sizeof(char));//for additional carry & ending so it's longer +1 +1
int idx = 0;
while (longer>0){
int v1=0;
int v2=0;
if (l1-1>=0)
v1= a[--l1]-'0';
if (l2-1>=0)
v2= b[--l2]-'0';
//printf("%d + %d\n", v1, v2);
int sum = carry+v1+v2;
carry = (sum>1)? 1: 0;
ret[idx++]= ((sum& 0x1)==1)? '1' :'0';
longer--;
}
if (carry>0)
ret[idx++]='1';
//printf("idx %d carry %d\n", idx,carry);
for (int i=0; i<idx/2;i++)
reverse(&ret[i], &ret[idx-1-i]);
return ret;
}
看來while 可以改成 l1>0 || l2>0 || carry 結果又改出無窮回圈 囧
#define max(a,b) (a>b)?(a):(b)
void reverse(char *a, char *b){
char tmp = *a;
*a=*b;
*b=tmp;
}
char* addBinary(char* a, char* b) {
int l1 = strlen(a);
int l2 = strlen(b);
int longer= max(l1, l2);
int carry = 0;
char *ret = calloc(longer+2, sizeof(char));//for additional carry & ending so it's longer +1 +1
int idx = 0;
while (l1>0 || l2>0 || carry){
int v1=0;
int v2=0;
if (l1-1>=0)
v1= a[--l1]-'0';
if (l2-1>=0)
v2= b[--l2]-'0';
int sum = carry+v1+v2;
carry = (sum>1)? 1: 0;
ret[idx++]= ((sum& 0x1)==1)? '1' :'0';
}
for (int i=0; i<idx/2;i++)
reverse(&ret[i], &ret[idx-1-i]);
return ret;
}
[20260709] 更新
有一點懶得修！ 這個算是復健題XD 輸入小的時候應該是對的～
但長度一長就一定是錯的要重寫～就先貼下吧. 沒想到當年我竟然是用C++寫的XD
int str2int(char* s1, int len){
int ret=0;
for (int i=0; i<len;i++)
{
ret = (ret<<1) + (s1[i] & 0x1);
}
// printf("ret %d\n",ret);
return ret;
}
#define STRLEN INT_MAX
void swap(char *a, char *b){
char tmp = *a;
*a = *b;
*b = tmp;
return;
}
char* int2str(int val){
char *ret = calloc (STRLEN,sizeof(char));
int idx = 0;
//printf("int2str val %d\n",val);
while (val>0)
{
if (val&0x1 == 1)
ret[idx++]='1';
else
ret[idx++]='0';
val= val>>1;
//printf("int2str idx %d, [%c]\n",idx, ret[idx-1]);
}
//printf("int2str idx(len) %d\n",idx);
char *reverse= calloc(idx+1, sizeof(char));
// char *reverse = (char*) realloc(ret, idx*sizeof(char));
for (int i=0; i<idx; i++)
reverse[idx-i-1]= ret[i];
#if 0
printf("int2str idx %d, strlen %d\n",idx, strlen(reverse));
for (int i=0; i<idx/2; i++)
{
swap(&reverse[i], &reverse[idx-i]);
}
#endif
if (idx==0)
return "0";
return reverse;
}
char* addBinary(char* a, char* b) {
int l1 = strlen(a);
int l2 = strlen(b);
printf("l1 %d l2 %d\n",l1,l2);
int sum = str2int(a,l1) + str2int(b,l2);
//printf("sum %d\n",sum);
return int2str(sum);
// return NULL;
}
