# Minimum Distance Between BST Nodes Problem & Solution

Given the `root` of a Binary Search Tree (BST), return the minimum difference between the values of any two different nodes in the tree.

## C++ Solution

``````#pragma GCC optimize("Ofast")
#pragma GCC optimization("max-inline-insns-recursive-auto")

static const int _=[](){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();

/**
* struct TreeNode {
*   int val;
*   TreeNode *left;
*   TreeNode *right;
*   TreeNode() : val(0), left(nullptr), right(nullptr) {}
*   TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
*   TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int minDiffInBST(TreeNode* root) {
TreeNode* prev = nullptr;
int diff = numeric_limits<int>::max();

minDiffInBST(root, &prev, diff);

return diff;
}

private:
void minDiffInBST(TreeNode* root, TreeNode** prev, int& diff) {
if (root == nullptr) {
return;
}

minDiffInBST(root->left, prev, diff);
if (*prev != nullptr) {
diff = min(diff, root->val - (*prev)->val);
}

*prev = root;
minDiffInBST(root->right, prev, diff);
}
};
``````

## Start Here

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