67 lines
1.5 KiB
Rust
67 lines
1.5 KiB
Rust
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/**
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* [7] Reverse Integer
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*
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* 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.
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* Assume the environment does not allow you to store 64-bit integers (signed or unsigned).
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*
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* <strong class="example">Example 1:
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*
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* Input: x = 123
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* Output: 321
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*
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* <strong class="example">Example 2:
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*
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* Input: x = -123
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* Output: -321
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*
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* <strong class="example">Example 3:
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*
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* Input: x = 120
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* Output: 21
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*
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*
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* Constraints:
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*
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* -2^31 <= x <= 2^31 - 1
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*
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*/
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pub struct Solution {}
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// problem: https://leetcode.cn/problems/reverse-integer/
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// discuss: https://leetcode.cn/problems/reverse-integer/discuss/?currentPage=1&orderBy=most_votes&query=
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// submission codes start here
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impl Solution {
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pub fn reverse(x: i32) -> i32 {
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let (num, negative) = if x < 0 {
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(-x, true)
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} else {
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(x, false)
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};
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let str = num.to_string();
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let mut str: String = str.chars().rev().collect();
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if negative {
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str.insert(0, '-');
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}
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str.parse::<i32>().unwrap_or_else(|_| 0)
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}
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}
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// submission codes end
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_7() {
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assert_eq!(321, Solution::reverse(123));
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assert_eq!(-321, Solution::reverse(-123));
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assert_eq!(21, Solution::reverse(120));
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assert_eq!(0, Solution::reverse(0));
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}
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}
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