leetcode倒转整数--snprintf性能不行

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <limits>
int reverse(int x) {
    long sum = 0;
    while (x) {
        sum = sum * 10 + x % 10;
        x = x / 10;
    }
    if (sum > std::numeric_limits<int>::max() || sum < std::numeric_limits<int>::min()) {
        return 0;
    }
    return static_cast<int>(sum);
}
int reverse1(int x) {
    static const char *MAX_INT_VALUE = "2147483647";
    static const int MAX_INT_SIZE = 10;
    bool positive = true;
    char buf[32] = "";
    if (x < 0) {
        if (std::numeric_limits<int>::min() == x) {
            return 0;
        }
        x = -x;
        positive = false;
    }
    //std::string str = std::to_string(x);      // 比snprintf更慢
    snprintf(buf, sizeof(buf), "%d", x);        // 慢
    return 0;
    char ch = 0;
    int len = strlen(buf);
    int i = 0;
    int j = len -1;
    if ((MAX_INT_SIZE == len) && buf[j] >= '3') {
        return 0;
    }
    for (;i < j;i++,j--) {
        ch = buf[i];
        buf[i] = buf[j];
        buf[j] = ch;
    }
    if (MAX_INT_SIZE == len) {
        if (strcmp(buf, MAX_INT_VALUE) > 0) {
            return 0;
        }
    }
    if (true == positive) {
        return atoi(buf);
    }
    return -atoi(buf);
}
int main() {
    for (int i = -99999999;i <= 9999999;i++) {
        reverse(i);         // 3.317s
       // reverse1(i);          // 10.649s
    }
    
    return 0;
}