题解 | #大数加法#

#include <string>
#include <vector>
class Solution {
  public:
    string solve(string s, string t) {
        // write code here
        string ans;
        int i, j;
        int s_len = s.length();
        int t_len = t.length();
        int max_len = max(s_len, t_len);
        vector<int> a, b; //a->s,b->t;
        vector<int> c;
        for (i = 0; i < s_len; i++) {
            a.push_back(s[i] - '0');
        }
        for (i = 0; i < t_len; i++) {
            b.push_back(t[i] - '0');
        }
        for (i = s_len - 1, j = t_len - 1; i >= 0 && j >= 0; i--, j--) {
            c.push_back(a[i] + b[j]);
        }
        if (i < 0) {
            while (j >= 0) {
                c.push_back(b[j]);
                j--;
            }
        }
        if (j < 0) {
            while (i >= 0) {
                c.push_back(a[i]);
                i--;
            }
        }
        for (i = 0; i < c.size(); i++) {
            if (c[i] >= 10) {
                int count = c[i] / 10;
                c[i] = c[i] % 10;
                if (i == c.size() - 1) {
                    c.push_back(count);
                    break;
                }
                c[i + 1] += count;
            }
        }
        for (i = c.size() - 1; i >= 0; i--) {
            ans += to_string(c[i]);
        }
        return ans;
    }
};