/**
 * [7] Reverse Integer
 *
 * Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0.
 * Assume the environment does not allow you to store 64-bit integers (signed or unsigned).
 *  
 * <strong class="example">Example 1:
 * 
 * Input: x = 123
 * Output: 321
 * 
 * <strong class="example">Example 2:
 * 
 * Input: x = -123
 * Output: -321
 * 
 * <strong class="example">Example 3:
 * 
 * Input: x = 120
 * Output: 21
 * 
 *  
 * Constraints:
 * 
 * 	-2^31 <= x <= 2^31 - 1
 * 
 */
pub struct Solution {}

// problem: https://leetcode.cn/problems/reverse-integer/
// discuss: https://leetcode.cn/problems/reverse-integer/discuss/?currentPage=1&orderBy=most_votes&query=

// submission codes start here

impl Solution {
    pub fn reverse(x: i32) -> i32 {
        let (num, negative) = if x < 0 {
            (-x, true)
        } else {
            (x, false)
        };

        let str = num.to_string();
        let mut str: String = str.chars().rev().collect();
        if negative {
            str.insert(0, '-');
        }

        str.parse::<i32>().unwrap_or_else(|_| 0)
    }
}

// submission codes end

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_7() {
        assert_eq!(321, Solution::reverse(123));
        assert_eq!(-321, Solution::reverse(-123));
        assert_eq!(21, Solution::reverse(120));
        assert_eq!(0, Solution::reverse(0));
    }
}