Cinte's Leetcode Record
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7. 整数反转

Posted on Edited on In Disqus:
Symbols count in article: 576 Reading time ≈ 1 mins.

7. 整数反转

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class Solution {
public:
    int reverse(int x) {
        int ret = 0;
        bool positive = true;
        if(x == INT_MIN)
            return 0;
        if(x < 0)
        {
            positive = false;
            x = -x;
        }
        while(x)
        {
            int num = x % 10;
            x /= 10;
            if(ret > INT_MAX / 10 || (ret == INT_MAX / 10 && num > INT_MAX % 10))
                return 0;
            ret = ret * 10 + num;
        }
        return positive ? ret : -ret;
    }
};

引入一个小trick

1633332629963.png 
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class Solution {
public:
    int reverse(int x) {
        int ret = 0;
        while(x)
        {
            if(ret > INT_MAX / 10 || ret < INT_MIN / 10)
                return 0;
            int num = x % 10;
            x /= 10;
            ret = ret * 10 + num;
        }
        return ret;
    }
};