题解 | 多少种分类

#include <vector>
class Coins {
    const int mod = 1000000007;
public:
    int countWays(int n) {
        // write code here
        vector<int> dp(n+1,0);
        dp[0]=1;
        for (auto coin: {1,5,10,25})
        {
            for(auto i=coin;i<=n;i++)
            {
                dp[i] = (dp[i] +dp[i-coin])%mod; 
            }
        }
     return dp[n];

    }
};