题解 | #最小邮票数#01背包模板题，记住就行。

#include<iostream>
#include <vector>
#include <climits>
using namespace std;
int main() {
    int m, n;
    while (cin >> m >> n) {
        vector<int> dp(m + 1, INT_MAX);
        dp[0] = 0;
        for (int i = 0; i < n; i++) {
            int value;
            cin >> value;
            for (int j = m; j >= value; j--) {
                if (dp[j - value] != INT_MAX && dp[j - value] + 1 < dp[j]) {
                    dp[j] = dp[j - value] + 1;
                }
            }
        }
        cout << (dp[m] == INT_MAX ? 0 : dp[m]) << endl;
    }
    return 0;
}