#include <stdio.h>
inline int abs(int x) {return (x > 0) ? x : -1 * x;}

int n, k;
int nk[16];
int len = 0;
int ans[50];
const char map[50] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q'};

void initNk() {
    nk[len] = 1;
    do {
        len++;
        nk[len] = k * nk[len - 1];
    } while (abs(nk[len]) <= abs(n));
}

int main() {
    scanf("%d%d", &n, &k);
    int cpy = n;
    initNk();
    int cur;
    for (int i = len; i >= 0; i--) {
        if (n % nk[i] == 0) {
            cur = n / nk[i];
            n -= nk[i] * cur;
        } else {
            cur = n / nk[i] + 1;
            n -= nk[i] * cur;
        }
        ans[len - i] = cur;
    for (int i = len; i >= 0; i--) {
        while (ans[i] >= -1*k) ans[i] -= -1*k, ans[i - 1] -= 1;
    }
    bool fronted = true;
    printf("%d=", cpy);
    for (int i = 0; i <= len; i++) {
        if (fronted) {
            if (ans[i] != 0) {
                fronted = false;
            } else {
                continue;
            }
        }
        //if (ans[i] == -1) {
            //printf("1%c", map[-1*k-1]);
            //continue;
        //}
        printf("%c", map[ans[i]]);
    }
    printf("(base%d)", k);
    return 0;
}

本人逆天代码跑样例1会RE但是能AC 输入输出

30000 -2 30000=011010101110000(base-2)

（本人彩笔）但是构思的解决方案是注释掉的几行，请各位巨佬检查一下是否有误