DFS+记忆化搜索

int f[100];
class Solution {
public:
    int ans = 1;
    void dfs(int x,int mult){
        //cout<<x<<" "<<mult<<endl;
        if(x<0) return;
        if(mult<=f[x]) return;//剪枝
        f[x] = mult;
        if(x == 0){
            ans = max(ans,mult);
            return ;
        }
        for(int i=2;i<=x;i++){
            dfs(x-i, mult*i);
        }

    }
    int maxProductAfterCutting(int length) {
        if(length == 2) return 1;
        dfs(length,1);
        return ans;
    }
};