问题:如 123———>321 -123————>-321 120————>21 怎么玩呢?
注意要考虑整数的范围是-231次方到231-1
public int reverse(int x) { int rev = 0; while (x != 0) { int pop = x % 10; x /= 10; if (rev > Integer.MAX_VALUE/10 || (rev == Integer.MAX_VALUE / 10 && pop > 7)) return 0; if (rev < Integer.MIN_VALUE/10 || (rev == Integer.MIN_VALUE / 10 && pop < -8)) return 0; rev = rev * 10 + pop; } return rev; }
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