Socks problem - Can you help me with better logic ?

Problem:

Solution:

static int sockMerchant(int n, int[] ar) {

        int cnt=0;

        Arrays.sort(ar);

        for(int i=0;i<n-1;i++)

            if(ar[i]==ar[i+1]){cnt++;i++;}

        return cnt;

    }

Counting Valleys - Can you find a better solution? (Code in Java)

Problem:

Java8 Code:

static int countingValleys(int n, String s) {

        int lvl=0,vc=0;

        boolean valleyFlag=false;

        char[] stps=s.toCharArray();

        

        for(int i=0;i<stps.length;i++)

        {

            if(stps[i]=='D') lvl--;

            else if(stps[i]=='U') lvl++;

            if(lvl==0 && valleyFlag==true)

            {

                valleyFlag=false;

                vc++;

            }

            if(lvl==-1) valleyFlag=true;

        }

        return vc;

    }