all paths in a tree which sum up to a value

/* From Cracking the Coding Interview 4-8.

You are given a binary tree in which each node contains a value.

 Design an algorithm to print all paths which sum up to that value.

 Note that it can be any path in the tree - it does not have to start at the root. */

/* I use the algorithm suggested in the book for the implementation (with slight improvement). The key point to the algorithm is: On every node, we look “up” to see if we’ve found the sum.

*/

struct node {

    node(int v): value(v), left(nullptr), right(nullptr) { }

    int value;

    node * left, * right;

};

void printPath(vector<int> & v, int i) {

    for (int u = i; u < (int) v.size(); ++u) {

     cout << v[u] << " ";

    }

    cout << endl;

}

void sumInPath(node * n, vector<int> v, const int & sum) {

    if (!n) {

        return;

    }

    v.push_back(n->value);

    int total = 0;

    for (int i = (int) v.size()-1; i >= 0; --i) {

     total += v[i];

     if (total == sum) {

          printPath(v, i);

     }

    }

    if (n->left) {

     sumInPath(n->left, v, sum);

    }

    if (n->right) {

     sumInPath(n->right, v, sum);

    }

}