MacQ:

1.line function

2.remove empty char from a string

SqPoint:

1.find duplicated int

(1)set (2)math (3)manual hash

2.multithreading

Schat:

1.pascal

(1)recursive (2)hash (3)duplicates BB: 1.changesToMakeAnagram 2.isBST 3.copy random pointer

// This is the text editor interface. 
// Anything you type or change here will be seen by the other person in real time.

//                 5
//            3        8
//        1      6   7    9  



struct Node {
    Node* left;
    Node* right;
    int val;
};

bool checkSubTree(Node* n, int min, int max){
    if(n==NULL) return true;

    return (n->val < max && n->val > min) && 
            checkSubTree(n->left,min,n->val) &&
            checkSubTree(n->right,n->val,max);
}

bool isBST(Node* n) {
    checkSubTree(n,INT_MIN,INT_MAX);
}