# [2169. Count Operations to Obtain Zero](https://leetcode.com/problems/count-operations-to-obtain-zero/)


## 题目

You are given two **non-negative** integers `num1` and `num2`.

In one **operation**, if `num1 >= num2`, you must subtract `num2` from `num1`, otherwise subtract `num1` from `num2`.

- For example, if `num1 = 5` and `num2 = 4`, subtract `num2` from `num1`, thus obtaining `num1 = 1` and `num2 = 4`. However, if `num1 = 4` and `num2 = 5`, after one operation, `num1 = 4` and `num2 = 1`.

Return *the **number of operations** required to make either* `num1 = 0` *or* `num2 = 0`.

**Example 1:**

```
Input: num1 = 2, num2 = 3
Output: 3
Explanation:
- Operation 1: num1 = 2, num2 = 3. Since num1 < num2, we subtract num1 from num2 and get num1 = 2, num2 = 3 - 2 = 1.
- Operation 2: num1 = 2, num2 = 1. Since num1 > num2, we subtract num2 from num1.
- Operation 3: num1 = 1, num2 = 1. Since num1 == num2, we subtract num2 from num1.
Now num1 = 0 and num2 = 1. Since num1 == 0, we do not need to perform any further operations.
So the total number of operations required is 3.

```

**Example 2:**

```
Input: num1 = 10, num2 = 10
Output: 1
Explanation:
- Operation 1: num1 = 10, num2 = 10. Since num1 == num2, we subtract num2 from num1 and get num1 = 10 - 10 = 0.
Now num1 = 0 and num2 = 10. Since num1 == 0, we are done.
So the total number of operations required is 1.

```

**Constraints:**

- `0 <= num1, num2 <= 10^5`

## 题目大意

给你两个 非负 整数 num1 和 num2 。每一步 操作 中，如果 num1 >= num2 ，你必须用 num1 减 num2 ；否则，你必须用 num2 减 num1 。

- 例如，num1 = 5 且 num2 = 4 ，应该用 num1 减 num2 ，因此，得到 num1 = 1 和 num2 = 4 。然而，如果 num1 = 4且 num2 = 5 ，一步操作后，得到 num1 = 4 和 num2 = 1 。

返回使 num1 = 0 或 num2 = 0 的 操作数 。

## 解题思路

- 简单题，按照题意模拟，每次两个数字相减，便累加操作次数。当某个数字变为 0 时，输出操作次数。

## 代码

```go
package leetcode

func countOperations(num1 int, num2 int) int {
	res := 0
	for num1 != 0 && num2 != 0 {
		if num1 >= num2 {
			num1 -= num2
		} else {
			num2 -= num1
		}
		res++
	}
	return res
}
```