==数组 Medium==

40.（162）Find Peak Element

JAVA

//斜率思想，二分法class Solution {    public int findPeakElement(int[] nums) {        int l=0,r=nums.length-1;        while(l
    
     nums[mid+1])                r = mid;            else                l = mid+1;        }        return l;    }}
    

41.（731）My Calendar II

JAVA

public class MyCalendarTwo {    List
    
      calendar;    List
     
       overlaps;//已经重叠过一次的区间    MyCalendarTwo() {        calendar = new ArrayList();        overlaps = new ArrayList();    }    public boolean book(int start, int end) {        for (int[] iv: overlaps) {            if (iv[0] < end && start < iv[1]) return false;        }        for (int[] iv: calendar) {            if (iv[0] < end && start < iv[1])                overlaps.add(new int[]{Math.max(start, iv[0]), Math.min(end, iv[1])});        }        calendar.add(new int[]{start, end});        return true;    }}
     
    

42.（153）Find Minimum in Rotated Sorted Array

JAVA

class Solution {    public int findMin(int[] nums) {        int l = 0;        int r = nums.length-1;        while(l

class Solution {    public int findMin(int[] nums) {       return find(nums,0,nums.length-1);    }        public int find(int[] nums, int l, int r) {        if(nums[l] <= nums[r]) {            return nums[l];        }        int mid = (l + r) / 2;        return Math.min(find(nums,l,mid),find(nums,mid+1,r));    }}

43.（152）Maximum Product Subarray

JAVA

class Solution {    public int maxProduct(int[] nums) {        if(nums.length == 0){            return 0;        }        int maxPre = nums[0];        int minPre = nums[0];        int max = nums[0];        for(int i =1;i

44.（611）Valid Triangle Number

JAVA

class Solution {    public int triangleNumber(int[] nums) {        int count = 0;        Arrays.sort(nums);        for(int i =0;i
    
     nums[k])                    k++;                count += k-j-1;            }        }        return count;    }}
    

45.（621）Task Scheduler

JAVA

//计算休眠时间，再加上任务时间等于总时间class Solution {    public int leastInterval(char[] tasks, int n) {        int[] map = new int[26];        for(char c : tasks)            map[c-'A']++;        Arrays.sort(map);        int idle = (map[25] -1)*n;        for(int i=24;i>=0&&map[i]>0;i--){            idle -= Math.min(map[i],map[25]-1);        }        return idle >0 ? tasks.length+idle:tasks.length;    }}