LeetCode 456, 650

LeetCode 记录

456. 132 Pattern

Given a sequence of n integers a1, a2, …, an, a 132 pattern is a subsequence ai, aj, ak such that i < j < k and ai < ak < aj. Design an algorithm that takes a list of n numbers as input and checks whether there is a 132 pattern in the list.

function find132pattern(nums){
    let min=100000000000;     
    for(let i=0;i<nums.length-1;i++){
        min=Math.min(nums[i],min);   //存当前最小值
        for(let k=i+1;k<nums.length;k++){
            if(nums[k]<nums[i]&&min<nums[k]){
                return true;
            }
        }
    }
    return false;
}                                                                 

650. 2 Keys Keyboard

Initially on a notepad only one character ‘A’ is present. You can perform two operations on this notepad for each step:

Copy All: You can copy all the characters present on the notepad (partial copy is not allowed).
Paste: You can paste the characters which are copied last time.
Given a number n. You have to get exactly n ‘A’ on the notepad by performing the minimum number of steps permitted. Output the minimum number of steps to get n ‘A’.

function minSteps(n){
    let step=0;
    let board='';
    let all='A';
    const copy=function (all){
        return all;   //复制的动作，将现有的A复制到剪贴板
    }
    const paste=function(board){
        step++;
        all=all+board;   //粘贴，把现在的和剪贴板中的连起来
    }
    while(all.length<n){
        if(n%all.length==0){   //可以整除就复制
            board=copy(all);
            step++;
        }
        paste(board);   //不能整除就粘贴
    }
    return step;
}