View Compilation Error

0_0_38469600_11547.cpp: In function 'int main()':
0_0_38469600_11547.cpp:28:23: error: 'j' was not declared in this scope
             dp[i - 2][j - 1] + (ar[i] - ar[i - 1]) * (ar[i] * ar[i - 1])
                       ^
0_0_38469600_11547.cpp:29:28: error: 'j' was not declared in this scope
             for(int j = 1; j <= k && j <= i/2; j ++)
                            ^
0_0_38469600_11547.cpp:29:43: error: 'i' was not declared in this scope
             for(int j = 1; j <= k && j <= i/2; j ++)
                                           ^