vector with same size running very slow than dynamically allocated array Edit topic

I have an array and vector both of same size and dimension. My code needs set operation to be performed on one of them. Now as i see, in vector their are set operation functions already present, but not for array. Since my array/vector is very big, using array for set operation is slow i think, so i want to use vector, but i dont know why when i run vector with same size program executes very slow. As i found that their is no need of dynamically allocating vectors. So what should i do now? My array is like:

Code:

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#define sp1(m, n, o) (array1[dim2 * dim3 * m + dim3 * n + o])
int * array1 = (int *)malloc(dim1 * dim2 * sizeof(int));

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And my vector with fixed size is like:

Code:

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vector<vector<vector<int> > > p(dim1, vector<vector<int> >(dim1, vector <int>(dim2, dim3)));

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So now how do i make the this vector run faster so than after that i can do set_intersection operation on them easily?

Where the delete button in this page, by the way.

Quote:

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Originally Posted by dinesh999lama

Where the delete button in this page, by the way.

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Code:

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... vector <int>(dim2, dim3)

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This doesn't look right as this means a vector with dim2 elements with each one initialised to value dim3? I suspect the initial sizing of the vectors is not correct and that during usage p is being dynamically resized.

Consider

Code:

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vector<vector<vector<int> > > p(dim1, vector<vector<int> >(dim2, vector <int>(dim3)));

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How are you using p?

to assign the value to vector i'm doing p[i][j][k]=value, and accessing in similar way. and the vector initialization provided by u above is the correct one.