B - Buy One Carton of Milk

https://atcoder.jp/contests/abc331/tasks/abc331_b

思路

dfs递归搜索， 按照依此按照三种策略：

6个一打 - cost S

8个一打 - cost M

12个一打 - cost L

递归到叶子节点终止条件为， 总的cost超过预算N，记录此时花费，更新 mincost

Code

https://atcoder.jp/contests/abc331/submissions/48127455

int N, S, M, L;
int mincost = INT_MAX;


void dfs(int sum, int cost){
    if (sum >= N){
        if (cost < mincost){
            mincost = cost;
        }
        
        return;
    }
    
    dfs(sum+6, cost+S);
    dfs(sum+8, cost+M);
    dfs(sum+12, cost+L);
}

int main()
{
    cin >> N >> S >> M >> L;

    dfs(0, 0);

    cout << mincost << endl;

    return 0;
}