Hulu written test programming-big integer addition

I took part in Hulu's test on Friday. I had a lot of questions in 70 minutes and I was not prepared enough. It took 40 minutes for the first 10 multiple choice questions, the last five blank questions had to be left blank. In this case, the time is not enough. The subjects are basic algorithms, data structures, and simple reasoning. Or its own reasons. The following algorithm questions are also very basic. Big integer addition (you can compare the big integer multiplication ). I have done it before, but I have not noticed it due to time. Sorry, here is the code written after I come back. Remind yourself to have a good review. Do not waste time.

# Include <iostream> using namespace STD; int main () {// string S1 = "3213124324131254356342652624624"; string S2 = "4"; string S1 = "9999999999999999999999999999999999999999999999 "; if (s1.length ()> s2.length () {string TMP = S1; S1 = S2; S2 = TMP;} string result (s2.length (), '0 '); int advance = 0; int I, j; for (I = s2.length ()-1, j = s1.length ()-1; j> = 0; -- I, -- J) {result [I] = (S1 [J]-'0') + (s2 [I]-'0') + advance) % 10 + '0'; advance = (S1 [J]-'0 ') + (s2 [I]-'0') + advance)/10;} while (advance & I! =-1) // considering the equal digits of the two, you must determine whether I is-1. {result [I] = (s2 [I]-'0') + advance) % 10 + '0'; advance = (s2 [I]-'0 ') + advance)/10; -- I;} if (I! =-1) {While (I! =-1) {result [I] = S2 [I]; -- I ;}} else {result. insert (result. begin (), advance + '0');} cout <result <Endl; return 0 ;}

NOTE: For the sake of simplicity, if S1 is more than S2, the two will be exchanged to ensure that S2 is always more than S2. I don't know if this is necessary, but there is additional consumption.

In addition, the result string also uses the storage space, which is also relatively lazy and requires additional space consumption.

#include <iostream>#include <string>using namespace std;string add(string left, string right){int advance = 0;string res;int i, j;for(i = left.length() - 1, j = right.length() - 1; i >= 0 && j >= 0; --i, --j){int sum = left[i] - '0' + right[j] - '0' + advance;advance = sum / 10;sum %= 10;res.insert(0, 1, '0' + sum);}if(i > 0){for(int j = i; j >= 0; --j){int sum = left[j] - '0' + advance;advance = sum / 10;sum %= 10;res.insert(0, 1, '0' + sum);}}else if(j > 0){for(int i = j; i >= 0; --i){int sum = right[i] - '0' + advance;advance = sum / 10;sum %= 10;res.insert(0, 1, '0' + sum);}}if(advance != 0)res.insert(0, 1, '0' + advance);return res;}int main(){string res;string left = "12346", right ="4";res = add(left, right);cout<<res<<endl;return 0;}