7. Reverse Integer

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0.

Assume the environment does not allow you to store 64-bit integers (signed or unsigned).

class Solution {
    void reverse(string& s, int n,int i) {

        if(n<=i){return;}

        swap(s[i],s[n]);
        reverse(s,n-1,i+1);
    }
public:
    int reverse(int x) {
        if (x == 0) return 0;
        int flag = x > 0 ? 1 : -1;
        string sx = to_string(abs(x));
        reverse(sx, sx.length() - 1, 0);
        long lx = atol(sx.c_str()) * flag;
        return (lx > INT_MAX || lx < INT_MIN) ? 0 : lx;
    }
};