注：重点在fz()函数

#include <bits/stdc++.h>
using namespace std;

char c[25], b[25], ans[25];
int len;
bool vis;

bool pd() {
	for (int i = 1; i <= len; i++) {
		if (b[i] > ans[i]) return 1;
		if (b[i] < ans[i]) return 0;
	}
	return 0;
}

void zy() {
	for (int i = 1; i <= len; i++) ans[i] = b[i];
}

void dfs(int d, int x, int dt) { // 现在是第d个数，前x个数为一循环 
	if (d == len + 1) {
		//cout << (b+1) << "\n";
		if (pd()) {
			zy();
		}
		return ;
	}
	if (d > x) b[d] = b[(d - 1) % x + 1];
	else {
		b[d] = c[d] + dt;
	}
	if (b[d] < '0') return ;
	if (b[d] > c[d] && !vis) return ;
	if (b[d] < c[d]) vis = 1;
	int vis1 = vis;
	dfs(d + 1, x, 0);
	vis = vis1;
	if (d < x) dfs(d + 1, x, -1);
}

void fz(int dt) {
	for (int i = 1; i <= len; i ++) {
		ans[i] = '0';
		b[i] = c[1] + dt;
	}
	b[len + 1] = '\0';
	c[len + 1] = '\0';
	cout << (b + 1) << " " << (c + 1) << " " << ((b + 1) > (c + 1)) << "\n";
	if ((b + 1) <= (c + 1)) zy();
}

int main() {
	cin.tie(0); ios::sync_with_stdio(0);
	int T;
	ans[0] = '.';
	cin >> T;
	while (T--) {
		cin >> (c + 1);
		//cout << (c + 1) << "\n";
		len = strlen(c + 1);
		//cout << len << ": ";
		fz(-1);
		fz(0);

		ans[len + 1] = '\0';
		for (int i = 2; i <= len / 2; i++) {
			vis = 0;
			if (len % i == 0) {
				dfs(1, i, 0);
				dfs(1, i, -1);
			}
		}
		cout << (ans + 1) << "\n";
//		for (int i = 1; i <= len+1; i++) cout << ans[i];
//		cout << "\n";
	}
}
/*
1
303
*/

数据：

1
303

cout << (b + 1) << " " << (c + 1) << " " << ((b + 1) > (c + 1)) << "\n";

这一行的意思是，输出 b[1] ~ b[len + 1] ， c[1] ~ c[len + 1] 和 （b 是否大于 c）。

相应的输出是：

222 303 1
333 303 1

也就是说 222 比 303 大，333 比 303 大。

所以为什么会出现这样的错误呢？qwq