(SPOJ) Fechadura - Solution

Link to the problem: http://br.spoj.com/problems/FECHAD14/

The solution below used Greedy algorithm to solve this problem. Starting from the left, we increase or decrease the height of pin n and pin n+1. We only move forward when pin n has the desired height.


import java.io.*;
import java.util.*;

class Main {
    public void process() throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       
        String line = br.readLine();
        String[] s = line.split("\\s");
        int numPins = Integer.parseInt(s[0]);
        int height = Integer.parseInt(s[1]);
       
        line = br.readLine();
        s = line.split("\\s");
        int[] pins = new int[numPins];
        for (int i = 0; i < numPins; i++) {
            pins[i] = Integer.parseInt(s[i]);
        }
       
        int count = 0;
        for (int i = 0; i < numPins-1; i++) {
            while (pins[i] != height) {
                if (pins[i] < height) {
                    pins[i]++;
                    pins[i+1]++;
                }
                else {
                    pins[i]--;
                    pins[i+1]--;
                }
                count++;
            }
        }
       
        System.out.println(count);
       
        return;
    }
   
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main m = new Main();
        m.process();
       
        System.exit(0);
    }
}