[2841] A*B Problem (50pts WA & TLE代码)

TLE:

#include<iostream>  
#include<cstring>  
#include<algorithm>  
#define obj (void) 
const int L=1100; 
using namespace std;  
string mul(string a,string b)//高精度乘法a,b,均为非负整数  
{  
    string s;  
    int na[L],nb[L],nc[L],La=a.size(),Lb=b.size();//na存储被乘数，nb存储乘数，nc存储积  
    fill(na,na+L,0);fill(nb,nb+L,0);fill(nc,nc+L,0);//将na,nb,nc都置为0  
    for(int i=La-1;i>=0;i--) na[La-i]=a[i]-'0';//将字符串表示的大整形数转成i整形数组表示的大整形数  
    for(int i=Lb-1;i>=0;i--) nb[Lb-i]=b[i]-'0';  
    for(int i=1;i<=La;i++)  
        for(int j=1;j<=Lb;j++)  
        nc[i+j-1]+=na[i]*nb[j];//a的第i位乘以b的第j位为积的第i+j-1位（先不考虑进位）  
    for(int i=1;i<=La+Lb;i++)  
        nc[i+1]+=nc[i]/10,nc[i]%=10;//统一处理进位  
    if(nc[La+Lb]) s+=nc[La+Lb]+'0';//判断第i+j位上的数字是不是0  
    for(int i=La+Lb-1;i>=1;i--)  
        s+=nc[i]+'0';//将整形数组转成字符串  
    return s;  
}  
int main()  
{  
string add(string a,string b);
string mul(string a,string b);
bool cmp(string a);

    string a;  
    cin>>a; 
    string b;
    string dst="1";
    while(1){
    	if(cmp(mul(dst,a))){
		 cout<<dst<<" "<<mul(dst,a);exit(0);
		 }else{dst=add(dst,"1");}
	}
    return 0;  
}  
bool cmp(string a){
unsigned fff=0;
for(unsigned i=0;i<a.size()+1;i++)
(a[i]=='0'||a[i]=='1')? obj fff++: obj 0;
//printf("\t%u",fff);
return(fff==(unsigned)a.size());
}

string add(string a,string b)//只限两个非负整数相加  
{  
    string ans;  
    int na[L]={0},nb[L]={0};  
    int la=a.size(),lb=b.size();  
    for(int i=0;i<la;i++) na[la-1-i]=a[i]-'0';  
    for(int i=0;i<lb;i++) nb[lb-1-i]=b[i]-'0';  
    int lmax=la>lb?la:lb;  
    for(int i=0;i<lmax;i++) na[i]+=nb[i],na[i+1]+=na[i]/10,na[i]%=10;  
    if(na[lmax]) lmax++;  
    for(int i=lmax-1;i>=0;i--) ans+=na[i]+'0';  
    return ans;  
}  

WA:

#include<stdio.h>
#include<stdbool.h>
#include<string.h>
#include<stdlib.h>
#define obj (void) 
using namespace std;
int main(){
	unsigned k;
scanf("%u",&k);
bool cmp(const char* a);
char *s=(char*)malloc(sizeof(char)*1024*1024);
unsigned  sum;
for(unsigned i=k;i<10*10*10*10+1;i++)
{
for(unsigned b=1;b<10*10*10*10+1;b++){
sum=i*b;
sprintf(s,"%u",sum);
/*printf("%u*%u=%llu",i,b,sum);*/
cmp(s)? obj printf("%u %u",b,sum), obj exit(0): obj 0/*printf(":: NO\n")*/;
}
}
} 
bool cmp(const char* a){
unsigned fff=0;
for(unsigned i=0;i<strlen(a)+1;i++)
(a[i]=='0'||a[i]=='1')? obj fff++: obj 0;
//printf("\t%u",fff);
return(fff==(unsigned)strlen(a));
}