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package g2401_2500.s2460_apply_operations_to_an_array;

// #Easy #Array #Simulation #2022_12_20_Time_1_ms_(87.93%)_Space_42.4_MB_(89.13%)

/**
 * 2460 - Apply Operations to an Array\.
 *
 * Easy
 *
 * You are given a **0-indexed** array `nums` of size `n` consisting of **non-negative** integers.
 *
 * You need to apply `n - 1` operations to this array where, in the i^th operation ( **0-indexed** ), you will apply the following on the i^th element of `nums`:
 *
 * *   If `nums[i] == nums[i + 1]`, then multiply `nums[i]` by `2` and set `nums[i + 1]` to `0`. Otherwise, you skip this operation.
 *
 * After performing **all** the operations, **shift** all the `0`'s to the **end** of the array.
 *
 * *   For example, the array `[1,0,2,0,0,1]` after shifting all its `0`'s to the end, is `[1,2,1,0,0,0]`.
 *
 * Return _the resulting array_.
 *
 * **Note** that the operations are applied **sequentially** , not all at once.
 *
 * **Example 1:**
 *
 * **Input:** nums = [1,2,2,1,1,0]
 *
 * **Output:** [1,4,2,0,0,0]
 *
 * **Explanation:** We do the following operations: 
 *
 * - i = 0: nums[0] and nums[1] are not equal, so we skip this operation. 
 *
 * - i = 1: nums[1] and nums[2] are equal, we multiply nums[1] by 2 and change nums[2] to 0. The array becomes [1, **4** , **0** ,1,1,0]. 
 *
 * - i = 2: nums[2] and nums[3] are not equal, so we skip this operation. 
 *
 * - i = 3: nums[3] and nums[4] are equal, we multiply nums[3] by 2 and change nums[4] to 0. The array becomes [1,4,0, **2** , **0** ,0]. 
 *
 * - i = 4: nums[4] and nums[5] are equal, we multiply nums[4] by 2 and change nums[5] to 0. The array becomes [1,4,0,2, **0** , **0** ]. 
 *
 * After that, we shift the 0's to the end, which gives the array [1,4,2,0,0,0].
 *
 * **Example 2:**
 *
 * **Input:** nums = [0,1]
 *
 * **Output:** [1,0]
 *
 * **Explanation:** No operation can be applied, we just shift the 0 to the end.
 *
 * **Constraints:**
 *
 * *   `2 <= nums.length <= 2000`
 * *   `0 <= nums[i] <= 1000`
**/
public class Solution {
    public int[] applyOperations(int[] nums) {
        for (int i = 0; i < nums.length - 1; i++) {
            if (nums[i] == nums[i + 1]) {
                nums[i] *= 2;
                nums[i + 1] = 0;
            }
        }
        int index = 0;
        for (int i = 0; i < nums.length; i++) {
            if (nums[i] != 0) {
                nums[index] = nums[i];
                index++;
            }
        }
        for (int i = index; i < nums.length; i++) {
            nums[i] = 0;
        }
        return nums;
    }
}