LeetCode 783. Minimum Distance Between BST Nodes

Posted on Edited on In 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
const minDiffInBST = (root) => {
    let ans = Number.MAX_SAFE_INTEGER, prev = -1;
    const dfs = (root) => {
        if (root) {
            dfs(root.left);
            if (prev != -1)
                ans = Math.min(ans, root.val - prev);
            prev = root.val;
            dfs(root.right);
        }
    };
    dfs(root);
    return ans;
};
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
const minDiffInBST = (root) => {
    let ans = Number.MAX_SAFE_INTEGER, prev = -1;
    const stk = [];
    while (stk.length > 0 || root) {
        while (root) {
            stk.push(root);
            root = root.left;
        }
        root = stk.pop();
        if (prev != -1)
            ans = Math.min(ans, root.val - prev);
        prev = root.val;
        root = root.right;
    }
    return ans;
};