Given Length and Sum of Digits...（构造+贪心）

题目链接： Given Length and Sum of Digits…

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大致题意:

给出长度m，和s，计算十进制下每一位总和是s，长度是m的最小值和最大值

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解题思路:

构造+贪心

注意：不能有前导零

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AC代码:

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

int main() {
	int m, s; cin >> m >> s;
	if (s < 1 && m>1 || s > m * 9)
		cout << -1 << ' ' << -1 << endl;
	else {
		for (int i = m - 1, k = s; i >= 0; --i) {
			int x = max(0, k - 9 * i);
			if (!x && i == m - 1 && k)x = 1;
			cout << x; k -= x;
		}
		cout << ' ';
		for (int i = m - 1, k = s; i >= 0; --i) {
			int x = min(9, k);
			cout << x;
			k -= x;
		}
	}
	return 0;
}

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