高精度进制转换

#include <bits/stdc++.h>
using namespace std;int val(char c) { // 字符转值if (c >= '0' && c <= '9') return c - '0';if (c >= 'A' && c <= 'Z') return c - 'A' + 10;return c - 'a' + 36;
}char digitChar(int v) { // 值转字符if (v < 10) return '0' + v;if (v < 36) return 'A' + (v - 10);return 'a' + (v - 36);
}void mul(vector<int>& a, int m) { // 高精乘int carry = 0;for (int i = 0; i < (int)a.size(); i++) {int t = a[i] * m + carry;a[i] = t % 10;carry = t / 10;}while (carry) {a.push_back(carry % 10);carry /= 10;}
}void add(vector<int>& a, int v) { // 高精加int carry = v;for (int i = 0; i < (int)a.size(); i++) {int t = a[i] + carry;a[i] = t % 10;carry = t / 10;if (!carry) return;}while (carry) {a.push_back(carry % 10);carry /= 10;}
}int divi(vector<int>& a, int d) { // 高精除int r = 0;for (int i = (int)a.size() - 1; i >= 0; i--) {int t = r * 10 + a[i];a[i] = t / d;r = t % d;}while (a.size() > 1 && a.back() == 0)a.pop_back();return r;
}int main() {ios::sync_with_stdio(0),cin.tie(0);int x, y;string z;cin >> x >> y >> z;vector<int> value(1, 0);// x进制转十进制for (char c : z) {int d = val(c);mul(value, x);   // value = value * xadd(value, d);   // value += d}if (value.size() == 1 && value[0] == 0) {// 特判0cout << 0;return 0;}// 十进制转y进制string out;while (!(value.size() == 1 && value[0] == 0)) {int r = divi(value, y);   // value /= yout.push_back(digitChar(r));}reverse(out.begin(), out.end());cout << out;
}