Combination Sum III LeetCode solution in C++

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class Solution {
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 public:
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  vector<vector<int>> ans;
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  // declare temp global vector in this vector we will store temprary
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  // combinations
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  vector<int> temp;
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  void solve(int k, int n, int order) {
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    // check if our target became zero and combination size became zero then
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    // push temp vector inside the ans it means this temp vector combination
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    // having sum is equal to target and size of vector is equal to k
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    if (n == 0 && k == 0) {
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      ans.push_back(temp);
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      return;
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    }
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    // check if our target is less than zero then return
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    if (n < 0) return;
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    // take for loop and check for all posibility ahead of order
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    for (int i = order; i <= 9; i++) {
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      // push current index value
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      temp.push_back(i);
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      // call solve function for further posiblity
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      solve(k - 1, n - i, i + 1);
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      // Pop last push value
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      temp.pop_back();
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    }
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  }
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  vector<vector<int>> combinationSum3(int k, int n) {
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    solve(k, n, 1);
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    return ans;
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  }
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};