Skip to content
Programmingoneonone
Programmingoneonone
  • Home
  • CS Subjects
    • Internet of Things (IoT)
    • Digital Communication
    • Human Values
  • Programming Tutorials
    • C Programming
    • Data structures and Algorithms
    • 100+ Java Programs
    • 100+ C Programs
  • HackerRank Solutions
    • HackerRank Algorithms Solutions
    • HackerRank C problems solutions
    • HackerRank C++ problems solutions
    • HackerRank Java problems solutions
    • HackerRank Python problems solutions
Programmingoneonone

HackerRank Jim and the Skyscrapers problem solution

YASH PAL, 31 July 2024

In this HackerRank Jim and the Skyscrapers problem, the first line contains the number of skyscrapers. The next line contains space-separated integers representing the heights of the skyscrapers. print an integer that denotes the number of valid routes.

HackerRank Jim and the Skyscrapers problem solution

Problem solution in Python programming.

N = int(input())
heights = [int(x) for x in input().split()]

assert len(heights) == N

stack = []

result = 0

for h in heights:
    while len(stack) > 0 and stack[-1][0] < h:
        stack.pop()
    if len(stack) > 0 and stack[-1][0] == h:
        result += stack[-1][1]
        stack[-1] = (stack[-1][0], stack[-1][1] + 1) 
    else:
        stack.append((h, 1))
        
print(2 * result)
        

Problem solution in Java Programming.

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

public class Solution {

    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	int n = sc.nextInt();
	int[] arr = new int[n];
	for(int i=0; i < n;i++)
		arr[i] = sc.nextInt();
	
	Stack<Integer> stack = new Stack<Integer>();
	stack.add(0);
	long[] store = new long[n];
	long count =0;
	for(int i=1; i < n;i++){
		while(! stack.isEmpty() && arr[stack.peek()] < arr[i]){
			stack.pop();
		}
		if(! stack.isEmpty() && arr[stack.peek()] == arr[i]){
			store[i] = store[stack.pop()]+1;
			count += store[i];
		}
		stack.push(i);
	}
	System.out.println(count*2); 
    }
}

Problem solution in C++ programming.

#include <cstdio>
#include <vector>
#include <stack>
#include <algorithm>
using namespace std;

const int NMAX = 300010, CMAX = 1000010;

int N, V[NMAX], Right[NMAX];
stack<int> S;
vector<int> Val[CMAX];
long long Ans;

int main()
{

    scanf("%i", &N);
    for(int i = 1; i <= N; ++ i)
    {
        scanf("%i", &V[i]);
        Val[V[i]].push_back(i);
    }

    V[N + 1] = CMAX;

    S.push(N + 1);
    for(int i = N; i; -- i)
    {
        while(!S.empty() && V[S.top()] <= V[i]) S.pop();
        Right[i] = S.top();
        S.push(i);
    }

    for(int i = CMAX - 1; i >= 1; -- i)
    {
        int Ptr = 0;
        for(int j = 0; j < Val[i].size(); )
        {
            while(Ptr < Val[i].size() && Val[i][Ptr] <= Right[ Val[i][j] ]) Ptr ++;
            int Len = Ptr - j;
            Ans += 1LL * Len * (Len - 1);
            j = Ptr;
        }
    }

    printf("%lld", Ans);
}

Problem solution in C programming.

#include <assert.h>
#include <stdbool.h>
#include <stdio.h>

enum {
  size = 300000,
};

struct group {
  int height;
  int count;
};

struct group reachable[size];
int num_reachable;

int main() {
  int n;
  scanf("%d", &n);
  assert(n > 0);
  long long num_backwards = 0;
  scanf("%d", &reachable[0].height);
  reachable[0].count = 1;
  num_reachable = 1;
  for (int i = 1; i < n; i++) {
    int h;
    scanf("%d", &h);
    
    int a = 0, b = num_reachable;
    while (a < b) {
      const int m = a + (b - a) / 2;
      struct group* r = &reachable[m];
      if (r->height == h) {
       
        a = b = m;
      } else if (r->height > h) {
        
        a = m + 1;
      } else if (r->height < h) {
        
        b = m;
      }
    }
    struct group* g = &reachable[a];
    const bool found = a < num_reachable && g->height == h;
    if (found) {
      assert(g->height == h);
      
      num_backwards += g->count;
      
      g->count++;
    } else {
      
      assert(a == num_reachable || g->height < h);
      *g = (struct group){
        .height = h,
        .count = 1,
      };
    }
    num_reachable = a + 1;
  }
  printf("%lldn", 2 * num_backwards);
}

Problem solution in JavaScript programming.

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', _ => {
    inputString = inputString.trim().split('n').map(str => str.trim());

    main();
});

function readLine() {
    return inputString[currentLine++];
}

// Complete the solve function below.
function solve(nums) {
  const stack = [];
  let p = 0;

  for (const num of nums) {
    while (stack.length && stack[stack.length-1][0] < num) stack.pop();
    //console.log(stack)
    if (stack.length && stack[stack.length-1][0] === num) {

      p+=stack[stack.length-1][1];
      stack[stack.length-1][1]+=1;
    } else {
      stack.push([num,1])
    }
    //console.log(stack)
  }

  return p*2;

}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const arrCount = parseInt(readLine(), 10);

    const arr = readLine().split(' ').map(arrTemp => parseInt(arrTemp, 10));

    let result = solve(arr);

    ws.write(result + "n");

    ws.end();
}

coding problems solutions

Post navigation

Previous post
Next post

Pages

  • About US
  • Contact US
  • Privacy Policy

Programing Practice

  • C Programs
  • java Programs

HackerRank Solutions

  • C
  • C++
  • Java
  • Python
  • Algorithm

Other

  • Leetcode Solutions
  • Interview Preparation

Programming Tutorials

  • DSA
  • C

CS Subjects

  • Digital Communication
  • Human Values
  • Internet Of Things
  • YouTube
  • LinkedIn
  • Facebook
  • Pinterest
  • Instagram
©2025 Programmingoneonone | WordPress Theme by SuperbThemes