Reach a state where only one candy remains.

Find two candies and an empty location lying together along a line. (that is "candy-candy-empty" or "empty-candy-candy"). This pattern can be in horizontal or vertical direction.

Select the candy away from the empty location. Then select the empty location. The selected candy will jump over the adjacent one to the empty location (now the pattern will be "empty-empty-candy" or "candy-empty-empty"). The middle candy gets removed by this. Similarly, go on removing the candies one by one till you reach a state when there are no two candies together with an adjacent vacant position.

The app does collect user data, all the data is saved only on the mobile device.