算法学习记录（五十八）

问：

1. 剑指 Offer 14- II. 剪绳子 II
2. 剑指 Offer 15. 二进制中1的个数
3. 剑指 Offer 16. 数值的整数次方
4. 剑指 Offer 17. 打印从1到最大的n位数
5. 剑指 Offer 18. 删除链表的节点

解： 1.

const cuttingRope = function(n) {
    if (n < 4) return n - 1
    const mod = 1000000007
    let res = 1
    while (n > 4) {
        res = (res * 3) % mod 
        n -= 3
    }
    return res * n % mod
};

const hammingWeight = function(n) {
    let num = 0
    while ((n & (~n + 1)) !== 0) {
        num++
        n ^= (n & (~n + 1))
    }
    return num
};

const myPow = function(x, n) {
   function getRes(a, b) {
       if (b === 0) return 1
       if (b === 1) return a
       if (b === -1) return 1 / a
       if (b % 2 === 0) {
           const res = getRes(a, b / 2)
           return res * res
        } else {
           const res = getRes(a, (b - 1) / 2)
           return  res*res*x
        }
    }
    return getRes(x, n)
};

const printNumbers = function(n) {
    const target = (''+9).repeat(n)
    const res = []
    for (let i = 1; i <= +target; i++) {
        res.push(i)
    }
    return res
};

const deleteNode = function(head, val) {
    let curNode = head
    let pre = null
    while (curNode) {
        if (curNode.val === val) {
            if (curNode.val === head.val) {
                return curNode.next
            } else {
                pre.next = curNode.next
                return head
            }
        } else {
            pre = curNode
            curNode = curNode.next
        }
    }
};