Reverse Integer [LeetCode 7]

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/cyrususie/article/details/78850507

Analysis

---

边界问题要考虑，题目中范围是32位的有符号数，所以为$[-2^{31},+2^{31}-1]$。

Answer

---

#include <iostream>
#include <sstream>
#include <math.h>

using namespace std;

class Solution {
public:
    int reverse(int x) {
        stringstream ss;
        ss << x;
        string s1 = ss.str();
        cout << s1 << endl;
        string ans = "";
        if (s1.length() == 1) return x;
        if (s1[s1.length()-1] == '0') {

        } else {
            ans += s1[s1.length()-1];
        }
        for (int i = s1.length()-2; i > 0; i--) {
            cout << s1[i] << endl;
            ans = ans + s1[i];
        }
        if (s1[0] == '-') {
            ans = '-' + ans;
        } else {
            ans += s1[0];
        }
        cout << ans << endl;
        stringstream ss2;
        ss2 << ans;
        long int result = 0;
        ss2 >> result;
        if (abs(result) > pow(2, 31)-1) return 0;
        return result;
    }
};