712B - Memory and Trident - CodeForces Solution

#include <iostream>
#include <bits/stdc++.h>
#include <vector>
#include <math.h>
using namespace std;

int main(){
    vector<int> arr;
    string s;
    cin>>s;
    if(s.length()%2!=0){
        cout<<"-1";
        return 0;
    }
    int r=0,u=0,l=0,d=0;
    for(int i=0;i<s.length();i++){
        if(s[i]=='R'){
            r++;
        }
        else if(s[i]=='U'){
            u++;
        }
        else if(s[i]=='L'){
            l++;
        }
        else{
            d++;
        }
    }
    // cout<<r<<l<<u<<d;
    if(r==l && u==d){
        cout<<"0";
    }
    else{
        int h=abs(r-l);
        int v=abs(u-d);
        if((h+v)%2!=0){
            cout<<"-1";
        }
        else{
            cout<<(h+v)/2;
        }
    }
}