aplusb2.cpp

// Ivan Carvalho
// Solution to https://dmoj.ca/problem/aplusb2
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 10;
typedef vector<int> vi;
char entrada1[MAXN], entrada2[MAXN];
vi soma(vi A, vi B) {
    while (A.size() < B.size()) A.push_back(0);
    while (B.size() < A.size()) B.push_back(0);
    vi C;
    C.assign(A.size() + 5, 0);
    for (int i = 0; i < A.size(); i++) {
        C[i] += A[i] + B[i];
    }
    for (int i = 0; i < C.size(); i++) {
        int t_val = C[i] % 10;
        int passa = (C[i] - t_val) / 10;
        if (i + 1 < C.size()) {
            C[i] = t_val;
            C[i + 1] += passa;
        }
    }
    while (!C.empty() && C.back() == 0) C.pop_back();
    if (C.empty()) C.push_back(0);
    return C;
}
vi subtrai(vi A, vi B) {
    while (A.size() < B.size()) A.push_back(0);
    while (B.size() < A.size()) B.push_back(0);
    vi C;
    C.assign(A.size() + 5, 0);
    for (int i = 0; i < A.size(); i++) {
        C[i] += A[i] - B[i];
        if (C[i] < 0) {
            C[i] += 10;
            C[i + 1] -= 1;
        }
    }
    for (int i = 0; i < C.size(); i++) {
        int t_val = C[i] % 10;
        int passa = (C[i] - t_val) / 10;
        if (i + 1 < C.size()) {
            C[i] = t_val;
            C[i + 1] += passa;
        }
    }
    while (!C.empty() && C.back() == 0) C.pop_back();
    if (C.empty()) C.push_back(0);
    return C;
}
int main() {
    int TC;
    scanf("%d", &TC);
    while (TC--) {
        scanf("%s %s", entrada1, entrada2);
        string s1 = entrada1, s2 = entrada2;
        int flag1 = (s1[0] == '-'), flag2 = (s2[0] == '-');
        vi A, B;
        for (int i = 0; i < s1.size(); i++) {
            if (s1[i] == '-') continue;
            A.push_back(s1[i] - '0');
        }
        for (int i = 0; i < s2.size(); i++) {
            if (s2[i] == '-') continue;
            B.push_back(s2[i] - '0');
        }
        reverse(A.begin(), A.end());
        while (!A.empty() && A.back() == 0) A.pop_back();
        if (A.empty()) A.push_back(0);
        reverse(B.begin(), B.end());
        while (!B.empty() && B.back() == 0) B.pop_back();
        if (B.empty()) B.push_back(0);
        reverse(A.begin(), A.end());
        reverse(B.begin(), B.end());
        if (B.size() > A.size() || (B.size() == A.size() && B > A)) {
            swap(A, B);
            swap(flag1, flag2);
        }
        reverse(A.begin(), A.end());
        reverse(B.begin(), B.end());
        if (flag1 == 0 && flag2 == 0) {
            vi C = soma(A, B);
            reverse(C.begin(), C.end());
            for (int i = 0; i < C.size(); i++) printf("%d", C[i]);
            printf("\n");
        } else if (flag1 == 0 && flag2 == 1) {
            vi C = subtrai(A, B);
            reverse(C.begin(), C.end());
            for (int i = 0; i < C.size(); i++) printf("%d", C[i]);
            printf("\n");
        } else if (flag1 == 1 && flag2 == 0) {
            vi C = subtrai(A, B);
            reverse(C.begin(), C.end());
            if (C[0] != 0) printf("-");
            for (int i = 0; i < C.size(); i++) printf("%d", C[i]);
            printf("\n");
        } else {
            vi C = soma(A, B);
            reverse(C.begin(), C.end());
            if (C[0] != 0) printf("-");
            for (int i = 0; i < C.size(); i++) printf("%d", C[i]);
            printf("\n");
        }
    }
    return 0;
};
printf("\n");
}
}
return 0;
}