题解 | 实现压缩列稀疏矩阵

def compressed_col_sparse_matrix(dense_matrix):

    vals = []
    row_idx = []
    cnt = [0 for _ in range(len(dense_matrix[0]) + 1)]
    col_ptr = [0 for _ in range(len(dense_matrix[0]) + 1)]

    for i in range(len(dense_matrix)):
        for j in range(len(dense_matrix[0])):
            if dense_matrix[i][j] != 0:
                vals.append(dense_matrix[i][j])
                row_idx.append(i)
                cnt[j+1] += 1

    for i in range(1,len(dense_matrix)+1):
        tot = 0
        for j in range(i+1):
            tot += cnt[j]
        col_ptr[i] = tot
    


    return vals, row_idx, col_ptr


if __name__ == "__main__":
    dense_matrix = eval(input())
    vals, row_idx, col_ptr = compressed_col_sparse_matrix(dense_matrix)
    print(vals)
    print(row_idx)
    print(col_ptr)