7. Reverse Integer

發表於 | 分類於

problem

Given a 32-bit signed integer, reverse digits of an integer.

solution

  • 要注意是否會overflow，在每次將結果加到ret變數時都必須檢查是否overflow

    option 1

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    class Solution {
    public:
        int reverse(int x) {
            
            int ret = 0;
            while(x){
                if(abs(ret) > INT_MAX/10) return 0;
                ret = 10*ret + (x%10);
                x/=10;
            }
            return ret;
        }
    };

    analysis

  • time complexity O(1)
  • space complexity O(1)