比n大的最小不重复数

void Calculate(int a)
{
int pa = a;
int count = 0;
int b[20] = {0};

//将pa按位存储到数组b
while(pa > 0)
{
b[count++] = pa%10;
pa = pa/10;
}
bool flag = true; //是否有重复数
bool carryFlag = false; //是否产生进位

//从高位开始判断是否有重复数
int i,j,k;
count--;
for(i=count;i>0;i--)
{
if(b[i] == b[i-1])
{
flag = false;
b[i-1]++; //有可能产生进位
if(b[i-1]>9)
carryFlag = true;
break;
}
}

if(!flag) //如果存在重复位
{
int c = 0;
//将低位重复数后面的数都变成0101....
for(j = i-1;j>0;j--)
{
b[j-1] = c;
c = (c == 0 ? 1:0);
}

//处理进位
if(carryFlag)
{
int carry = 0;
for(j = i-1;j<=count + 1;j++)
{
b[j] = b[j] + carry;
if(b[j] >= 10)
{
carry = 1;
b[j] = b[j] - 10;
}
}
}
pa = 0;
for(i = (count=1 ? count + 1:count);i >=0;i--)
{
pa = pa *10 + b[i];
}
cout<<"the min no repeat number: "<<pa<<endl;
}
else
{
cout<<"the min no repeat number: "<<a<<endl;
return;
}
}

输入两个很大正数，输出它们的乘积
void Multiply(const char *a,const char *b)
{
assert(a!=NULL && b!=NULL);
int len_a = strlen(a);
int len_b = strlen(b);
int *c = new int[len_a+len_b];
memset(c,0,sizeof(int) *(len_a+len_b));
for(int i=0;i<len_a;i++)
{
for(int j=0;j<len_b;j++)
{
c[i+j+1] += (a[i]-'0')*(b[j]-'0');
}
}
for(int i=len_a+len_b-1;i>0;i--)
{
if(c[i]>=10)
{
int carry = c[i]/10;
c[i-1] = c[i-1] + carry;
c[i] = c[i] % 10;
}
}
char *d = new char[len_a + len_b];
int i=0;
while(c[i] == 0) ++i;
int j;
for(j=0;i<len_a+len_b;j++,i++)
{
d[j] = c[i] + '0';
}
d[j] = '';
for(int i=0;i<len_a+len_b;i++)
cout<<d[i];
cout<<endl;
}