请求在"m"中的成员'find'，这是非类类型的'int'

获取错误/code/Solution.cpp:8:14: error: request for member 'find' in 'm', which is of non-class type 'int' if(m.find(s)!=m.end())return;

我还试图将undered_map的位置更改为类外，但仍然得到同样的错误。

class Solution {
public:
int maxsum;
unordered_map<string,int>m;
void solve(int m,vector<int>a,int sum,int i){
string s = to_string(sum)+" "+to_string(i);
if(m.find(s)!=m.end())return;
m[s]++;
if(i==a.size())return;
if(sum+a[i]<m){maxsum=max(maxsum,sum+a[i]);
solve(m,a,sum+a[i],i+1);}
solve(m,a,sum,i+1);
}
int backPack(int m, vector<int> &a) {
// write your code here
maxsum=0;
solve(m,a,0,0);
return maxsum;
}
};