【当前无排名】挑战leetcode进入前1w名

李恒道

https://leetcode.cn/problems/spiral-matrix/submissions/558280257/?envType=study-plan-v2&envId=top-100-liked
一眼分界，但是边界没有控制太好...
然而执行击败97%...
其他人到底怎么写的啊，喂

var spiralOrder = function (matrix) {
  const result = []
  const tiems = Math.ceil(Math.min(matrix[0].length, matrix.length) / 2)
  for (let layout = 0; layout < tiems; layout++) {
    const leftUpPos = [layout, layout]
    const rightDownPos = [matrix[0].length - layout - 1, matrix.length - layout - 1]
    if (leftUpPos[0] == rightDownPos[0] && leftUpPos[1] == rightDownPos[1]) {
      result.push(matrix[leftUpPos[0]][leftUpPos[1]])
      continue;
    }
    if (leftUpPos[1] == rightDownPos[1]) {
      for (let posX = layout; posX <= rightDownPos[0]; posX++) {
        const num = matrix[layout][posX];
        result.push(num)
      }
      continue;
    }
    if (leftUpPos[0] == rightDownPos[0]) {
      for (let posY = leftUpPos[1]; posY <= rightDownPos[1]; posY++) {
        const num = matrix[posY][rightDownPos[0]];
        result.push(num)
      }
      continue;
    }
    for (let posX = layout; posX < rightDownPos[0]; posX++) {
      const num = matrix[layout][posX];
      result.push(num)
    }
    for (let posY = leftUpPos[1]; posY < rightDownPos[1]; posY++) {
      const num = matrix[posY][rightDownPos[0]];
      result.push(num)
    }
    for (let posX = rightDownPos[0]; posX > leftUpPos[0]; posX--) {
      const num = matrix[rightDownPos[1]][posX];
      result.push(num)
    }
    for (let posY = rightDownPos[1]; posY > layout; posY--) {
      const num = matrix[posY][layout];
      result.push(num)
    }
  }
  return result
};

李恒道

https://leetcode.cn/problems/rotate-image/submissions/558285211/?envType=study-plan-v2&envId=top-100-liked
边界问题+轮换
简单

var rotate = function (matrix) {
  const result = []
  const tiems = Math.ceil(Math.min(matrix[0].length, matrix.length) / 2)
  for (let layout = 0; layout < tiems; layout++) {
    const leftUpPos = [layout, layout]
    const rightDownPos = [matrix[0].length - layout - 1, matrix.length - layout - 1]
    if (leftUpPos[0] == rightDownPos[0] && leftUpPos[1] == rightDownPos[1]) {
      continue;
    }
    const distance=rightDownPos[0]-leftUpPos[0]

    for (let posX = 0; posX < distance; posX++) {
      const num1 = matrix[layout][leftUpPos[1] + posX];
      const num2 = matrix[leftUpPos[1] + posX][rightDownPos[0]];
      const num3 = matrix[rightDownPos[0]][rightDownPos[0] - posX];
      const num4 = matrix[rightDownPos[0] - posX][layout];
      matrix[leftUpPos[1] + posX][rightDownPos[0]] = num1
      matrix[rightDownPos[0]][rightDownPos[0] - posX] = num2
      matrix[rightDownPos[0] - posX][layout] = num3
      matrix[layout][leftUpPos[1] + posX] = num4
    }
  }
  return matrix
};

李恒道

https://leetcode.cn/problems/linked-list-cycle/submissions/558290040/?envType=study-plan-v2&envId=top-100-liked

利用单步双步实现判断环形

var hasCycle = function (head) {
    if (head?.next == null || head?.next?.next == null) {
        return false
    }
    let fast = head.next?.next
    let slow = head.next
    while (fast != slow && fast != null) {
        fast = fast.next?.next
        slow = slow.next
    }
    if (fast == slow) {
        return true
    }
    return false
};

李恒道

https://leetcode.cn/problems/search-a-2d-matrix-ii/submissions/558533072/?envType=study-plan-v2&envId=top-100-liked
以为是简单题
起手一个递归超时了...
然后上了一堆优化还超时
结果看到答案1可以直接暴力我人都傻了

var searchMatrix = function (matrix, target) {
    let x = 0, y = matrix[0].length - 1
    while (x < matrix.length && y >= 0) {
        const num = matrix[x][y]
        if (num == target) {
            return true
        } else if (num > target) {
            y--
        } else {
            x++
        }
    }
    return false
};

李恒道

https://leetcode.cn/problems/palindrome-linked-list/submissions/558533622/?envType=study-plan-v2&envId=top-100-liked
简单回文，另外搞了一个简单的链表数字生成的，不然调试太差了

const createNodeList = (arr) => {
    let head = {
        val: arr[0],
        next: null
    }
    let ret = head
    for (let index = 1; index < arr.length; index++) {
        const num = arr[index];
        head.next = {
            val: num,
            next: null
        }
        head = head.next

    }
    return ret
}

var reverse = (head) => {
    let ret = null
    while (head != null) {
        let node = head
        head = head.next
        node.next = ret
        ret = node
    }
    return ret
}
/**
 * @param {ListNode} head
 * @Return {boolean}
 */
var isPalindrome = function (head) {
    if (head.next == null) {
        return true
    }
    let slow = head
    let fast = head.next
    if (slow != null && fast == null) {
        return slow.val === head.val
    }
    while (fast?.next?.next != null) {
        fast = fast?.next?.next
        slow = slow.next
    }
    let step2 = slow.next
    step2 = reverse(step2)
    slow.next = null;
    while (head?.val == step2?.val && head?.val != null) {
        head = head.next
        step2 = step2.next
    }
    if (head == null) {
        return true
    }
    return false
};

王一之

厉害了 这么久了

李恒道

王一之 发表于 2024-8-26 09:47
厉害了 这么久了

才打了40题
mlgb到现在排名都没有....

王一之

李恒道 发表于 2024-8-26 16:55
才打了40题
mlgb到现在排名都没有....

我记得上千道的，进入前1w名有难度的

王一之

李恒道 发表于 2024-8-26 16:55
才打了40题
mlgb到现在排名都没有....

我提议新开一个catcode平台，重新进行排名

李恒道

https://leetcode.cn/problems/linked-list-cycle-ii/submissions/558710983/?envType=study-plan-v2&envId=top-100-liked
定理题，很早之前死记硬背的

var detectCycle = function (head) {
    let slow = head?.next
    let fast = head?.next?.next
    if (fast == null) {
        return null
    }
    while (fast !== slow) {
        fast = fast?.next?.next
        slow = slow?.next
    }
    if(fast===null){
        return null
    }
    let line = head
    while (line != slow) {
        slow = slow?.next
        line = line?.next
    }
    return line
};