#include <iostream> #include<vector> using namespace std; vector<int>v; int res=0; void traceback(int k,int n,int sum){//k从0开始 if(sum==40){res++;return;} else if(sum>40){return ;} else if(k==n) return ; traceback(k+1,n,sum+v[k]); traceback(k+1,n,sum); } int m...