[Codility Lessons] StoneWall(18/n)

[Lesson7] Stacks and Queues

StoneWall : Cover “Manhattan skyline” using the minimum number of rectangles

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Java Solution Link : https://codility.com/demo/results/training6U5CTB-8PS/

import java.util.*;

class Solution {
    public int solution(int[] H) {
        Stack<Integer> wall = new Stack<Integer>();
        int count = 0;
        for(int i = 0; i < H.length; i++){
            while(!wall.empty() && H[i] < wall.peek()){
                wall.pop();
            }
            if(wall.empty() || H[i] > wall.peek()){
                wall.push(H[i]);
                count++;
            }
        }
        return count;
    }
}

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PHP Solution

function solution($H) {
    $wall = array();
    $count = 0;
    foreach($H as $value){
        while(count($wall) > 0 && $value < end($wall)){
            array_pop($wall);    
        }    
        if(count($wall) == 0 || $value > end($wall)){
            array_push($wall, $value);
            $count++;
        }
    }
    return $count;
}