LeetCode 009 Palindrome Number
2016-05-01 06:26
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题目要求判断一个整数是否为回文。
先想到负数算不算?这题里面是不算的。
然后直接拿Reverse Integer来,判断reverse以后是否相等。
但是还可以更快,因为不需要判断溢出(溢出以后自然能得出不是回文),不需要产生一个完整的reverse。用代码解释更清楚:
先想到负数算不算?这题里面是不算的。
然后直接拿Reverse Integer来,判断reverse以后是否相等。
但是还可以更快,因为不需要判断溢出(溢出以后自然能得出不是回文),不需要产生一个完整的reverse。用代码解释更清楚:
int y = 0; while(y < x) { y = y * 10 + x % 10; x = x / 10; } return (x == y) /*偶数位*/ || (y / 10 == x) /*奇数位*/;
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