5.7

56. 合并区间

var sortRange = (range) => {
  if (range && range.length) {
    this.rangeList.push(range)
  }
  return this.rangeList.sort((a, b) => a[0] - b[0]);
}
var = merge(list, range) => {
  const list = sortRange(list, range)
  let res = [];
  let prev = list[0];
  for (let i = 1; i < list.length; i++) {
    let cur = list[i];
    if (prev[1] >= cur[0]) {
      prev[1] = Math.max(cur[1], prev[1]); 
    } else {
      res.push(prev);
      prev = cur;
    }
  }
  res.push(prev);
  return res;
}

LeetCode 1272. 删除区间

    var = removeCoveredRange(list, range) => {
        const [start, end] = range
        let res = []

        for (let j = 0; j < list.length; j++) {
            const [currentStart, currentEnd] = list[j]
            if(currentEnd <= start || currentStart >= end) {
                res.push(list[j]);
            } else {
                if (currentStart < start) {
                    res.push([currentStart, start]);
                }
                if (currentEnd > end) {
                    res.push([end, currentEnd]);
                }
            }
        }
        return res;
    }

113. 路径总和 II

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @param {number} targetSum
 * @return {number[][]}
 */
var pathSum = function(root, targetSum) {
    var res = []
    var tmp = []
    var dfs = (node, sum) => {
        if (node === null) return
        const newSum = targetSum - node.val
        tmp.push(node.val)

        // 到叶子节点
        if (node.left === null && node.right === null && newSum === 0) {
            res.push(tmp)
        }
        dfs(node.left, newSum)
        dfs(node.right, newSum)
        tmp.pop()
    }
    dfs(root, targetSum)
    return res
};

322. 零钱兑换

/**
 * @param {number[]} coins
 * @param {number} amount
 * @return {number}
 */
// dp[i] = Math.min(dp[i], dp[i - coin] + 1)
var coinChange = function(coins, amount) {
    let dp = new Array(amount + 1).fill(Infinity);// 初始化dp数组
    dp[0] = 0;// 面额0只需要0个硬币兑换

    for (let i = 1; i <= amount; i++) {// 循环面额
        for (let coin of coins) {// 循环硬币数组
            if (i - coin >= 0) {// 当面额大于硬币价值时
                // dp[i - coin]： 当前面额i减当前硬币价值所需要的最少硬币
                dp[i] = Math.min(dp[i], dp[i - coin] + 1);
            }
        }
    }

    return dp[amount] === Infinity ? -1 : dp[amount];
};

160. 相交链表

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */

/**
 * @param {ListNode} headA
 * @param {ListNode} headB
 * @return {ListNode}
 */
var getIntersectionNode = function(headA, headB) {
        if (headA === null || headB === null) {
            return null;
        }
        let pA = headA, pB = headB;
        // 双指针：两个速度相同，简单理解就是两个ListNode x + y = y + x
        while (pA != pB) {
            pA = pA == null ? headB : pA.next;
            pB = pB == null ? headA : pB.next;
        }
        return pA;
};