runtah

So, this week I saw a blog post somewhere where the poster claimed that if you cant solve the mentioned 5 problems each in under and hour, you aint no programmer, dev or software engineer. So, I went in and read the problems. 1-4 were easy but number 5 got me a worrying a little. And expected, I failed to solve that in under 1 hour yesterday. But today morning I solved that in less than 30 minutes. But whatever, I cant call myself a programmer anymore :(
Heres my approach though, using recursion:
Each i (from 1 through 9) has 2 different ways of connecting to the sequence.
1. Add itself to the closest sum (1 + 23 + 4 + .......)
2. Or concatenate itself (1 + 234 + ......)
So if we either add an i to the sequence that has reached it or we concatenate. Examples: .......8 + 9
.......89
Now the part before 8 has the same behavior with 8
.......7 + 8
.......78
This goes all the way back to 1 and 2
1 + 2
12
So, the program works something like this
Each branch ultimately ends on the leftmost call.
Code:

#include <cstdio>
#include <iostream>
#include <sstream>

using namespace std;

string i2s(int i) {
 stringstream op;
 op << i;
 return op.str();
}

int solveS(int i, int sum, string p) {

 if (i >= 10) {
 if (sum == 100) {
 cout << p + " = " << sum << endl;
 }
 return 0;
 }

 int iSum = 0;
 for (int j = i ; j<=9 ; j++) {
 iSum = iSum * 10 + j;
 if (i == 1) {
 solveS(j+1, iSum, i2s(iSum));
 } else {
 solveS(j+1, sum+iSum, p + " + " + i2s(iSum));
 solveS(j+1, sum-iSum, p + " - " + i2s(iSum));
 }
 }

 return 0;
}

int main() {

 //freopen("output.txt", "w+", stdout);

 solveS(1, 0, "");

 return 0;
}