Mar 18 | Datawhale 05~08 打卡

DAY 5

112. Path Sum (Easy)

113. Path Sum II (Medium)

101. Symmetric Tree (Easy)

DAY6

124. Binary Tree Maximum Path Sum (Hard)

199. Binary Tree Right Side View (Medium)

var rightSideView = function(root) {
    let queue = [];
    let res = [];
    queue.push(root);

    if (root === null) return res;
    
    while(queue.length !== 0) {
        let length = queue.length;
        let level = [];
        for(let i =0; i < length; i++){
            let node = queue.shift();
            level.push(node.val);
            if(node.left) {queue.push(node.left);}
            if(node.right) {queue.push(node.right);}
        }
        res.push(level[length-1]);
    }
    return res;
};

226. Invert Binary Tree (Easy)

var invertTree = function(root) {
    // a function for inverting node
    const invertNode = function(root, left, right) {
        let temp = left;
        left = right;
        right = temp;
        root.right = right;
        root.left = left;
    }
 
    const queue = [root];
    if(root === null) return root;
    while (queue.length) {
        let length = queue.length;
        while(length--) {
            let node = queue.shift();
            invertNode(node, node.left, node.right);
            if (node.left) queue.push(node.left);
            if (node.right) queue.push(node.right);
        }

    }
    return root;
};