AlgoPlan0531

# Minimum Subsequence in Non-Increasing Order
##key idea:
- select the largest value from the nums array
- add them till it satisfies the requirement
- boom

class Solution {
    public List<Integer> minSubsequence(int[] nums) {
        Arrays.sort(nums);
        int subsum = 0;
        int remainsum = 0;
        for (int i =0;i<nums.length;i++){
            remainsum+=nums[i];
        }
        List<Integer> result = new ArrayList();
        int cursor = nums.length-1;
        while (subsum <= remainsum){
            result.add(nums[cursor]);
            subsum+=nums[cursor];
            remainsum -=nums[cursor];
            cursor--;
        }
        return result;
    }
}

#count hills and valleys in an array
##key idea:
 - to find nearest non-equal nodes
    -if the nearest left node is not equal to index, assign it to be the left one; otherwise, no assignment
    -if the nearest right node is not equal to index, assign it to be the right one; otherwise, assign index to the right one
    -initiate left and right to be num[0] and num[1]
    
class Solution {
    public int countHillValley(int[] nums) {
        int count =0;
        int indx = 0;
        int nearleft = nums[0];
        int nearright =nums[1];
        while (indx< nums.length){
            if (indx ==0 || indx ==nums.length-1){
                //pass
            }else{
                if (nums[indx-1] !=nums[indx]){
                    nearleft = nums[indx-1];
                }else{
                    //no movement
                }
                if ( nums[indx+1] != nums[indx]){
                    nearright = nums[indx+1];
                }else{
                    nearright = nums[indx];
                }
             
               if (nearleft < nums[indx] && nums[indx] > nearright){
                    count++;
                    System.out.print(" there is a hill at "+ indx);
                }
                if (nearleft >nums[indx] && nums[indx]< nearright){
                    count++;
                    System.out.print(" there is a valley at "+ indx);
                }  
            }
            indx++;
            
        }
        return count;
    }
}