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| // @Title: 寻找最近的回文数 (Find the Closest Palindrome)
// @Author: 15816537946@163.com
// @Date: 2022-03-24 00:04:41
// @Runtime: 0 ms
// @Memory: 1.9 MB
func nearestPalindromic(n string) string {
m := len(n)
candidates := []int{int(math.Pow10(m-1)) - 1, int(math.Pow10(m)) + 1}
selfPrefix, _ := strconv.Atoi(n[:(m+1)/2])
for _, x := range []int{selfPrefix - 1, selfPrefix, selfPrefix + 1} {
y := x
if m&1 == 1 {
y /= 10
}
for ; y > 0; y /= 10 {
x = x*10 + y%10
}
candidates = append(candidates, x)
}
ans := -1
selfNumber, _ := strconv.Atoi(n)
for _, candidate := range candidates {
if candidate != selfNumber {
if ans == -1 ||
abs(candidate-selfNumber) < abs(ans-selfNumber) ||
abs(candidate-selfNumber) == abs(ans-selfNumber) && candidate < ans {
ans = candidate
}
}
}
return strconv.Itoa(ans)
}
func abs(x int) int {
if x < 0 {
return -x
}
return x
}
|