40pt 求条

#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;

string s;
int n, t, len;
int ans = 0x3f;

void dfs(int l, int r, int sum, int cnt) {
	if (r - l + 1 >= t) return;
	if (cnt >= ans) return;
	if (sum > n) return;
	if (r > len) return;
	if (r == len) {
		int res = 0;
		for (int i = l; i <= r; i++) {
			res *= 10;
			res += (s[i] - '0');
		}
		if (sum + res == n) ans = min(ans, cnt);
		return;
	}
	dfs(l, r + 1, sum, cnt);
	int res = 0;
	for (int i = l; i <= r; i++) {
		res *= 10;
		res += (s[i] - '0');
	}
	dfs(r + 1, r, sum + res, cnt + 1);
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);	cout.tie(0);
	cin >> s >> n;
	int m = n;
	len = s.length();
	s = '%' + s;
	while (m > 0) {
		t++;
		m /= 10;
	}
	dfs(1, 0, 0, 0);
	cout << ans;
	return 0;
}