error: ld returned 1 exit status 和 error:undefined reference

 1 #include<vector>
 2 #include<algorithm>
 3 #include<iostream>
 4 #include<cstdio>
 5 using namespace std;
 6 class Solution {
 7     static int** nv;
 8     static bool cmp(int x, int y){
 9         int lenx = nv[x][0];
10         int leny = nv[y][0];
11         for(int xi = lenx-1, yi = leny-1; xi > 0, yi > 0; xi--, yi--){
12             if(nv[x][xi] < nv[y][yi]) return true;
13             if(nv[x][xi] > nv[y][yi]) return false;
14         }
15         return false;
16     }
17 public:
18     vector<int> lexicalOrder(int n) {
19         nv = new int* [n+1];
20         for(int i = 1; i < n+1; i++){
21             nv[i] = new int[10];
22         }
23         for(int i = 1; i <= n; i ++){
24             int y = i;
25             int yi = 1;
26             while(y != 0){
27                 nv[i][yi++] = y % 10;
28                 y = y / 10;
29             }
30             nv[i][0] = yi;
31         }
32         vector<int> v;
33         for(int i = 1; i <= n; i ++){
34             v.push_back(i);
35         }
36         sort(v.begin(), v.end(), cmp);
37         return v;
38     }
39     // vector<int> lexicalOrderList(int start, int last, int s, int n, vector<int>& v){
40 
41     // }
42 
43 };
44 int main(){
45     Solution s;
46     vector<int> v = s.lexicalOrder(13);
47     for(int i = 0; i < v.size(); i ++){
48         cout << v[i] << " ";
49     }
50     cout << endl;
51     return 0;
52 }