Algorithm
Problem Name: Mathematics -
https://www.hackerrank.com/challenges/strange-grid/problem?isFullScreen=true
In this HackerRank in Mathematics -
A strange grid has been recovered from an old book. It has 5 columns and infinite number of rows. The bottom row is considered as the first row. First few rows of the grid are like this:
..............
..............
20 22 24 26 28
11 13 15 17 19
10 12 14 16 18
1 3 5 7 9
0 2 4 6 8
The grid grows upwards forever!
Your task is to find the integer in cth column in rth row of the grid.
Input Format
There will be two integers r and c separated by a single space.
Constraints
- 1 <= r < 2 * 109
- 1 <= c <= 5
Rows are indexed from bottom to top and columns are indexed from left to right.
Output Format
Output the answer in a single line.
Sample Input
6 3
Sample Output
25
Explanation
The number in the 6th row and 3rd column is 25.
Code Examples
#1 Code Example with C Programming
Code -
C Programming
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <math.h>>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>>
#include <string.h>
char* readline();
char* ltrim(char*);
char* rtrim(char*);
char** split_string(char*);
int parse_int(char*);
/*
* Complete the 'strangeGrid' function below.
*
* The function is expected to return an INTEGER.
* The function accepts following parameters:
* 1. INTEGER r
* 2. INTEGER c
*/
long int strangeGrid(int r, int c) {
long int ans,sum,rem;
if(r%2==0)
{
rem=r/2;
sum=10*(rem-1)+1;
ans=sum+(2*(c-1));
}
else
{
rem=r/2;
sum=10*(rem);
ans=sum+(2*(c-1));
}
return ans;
}
int main()
{
FILE* fptr = fopen(getenv("OUTPUT_PATH"), "w");
char** first_multiple_input = split_string(rtrim(readline()));
int r = parse_int(*(first_multiple_input + 0));
int c = parse_int(*(first_multiple_input + 1));
int result = strangeGrid(r, c);
fprintf(fptr, "%d\n", result);
fclose(fptr);
return 0;
}
char* readline() {
size_t alloc_length = 1024;
size_t data_length = 0;
char* data = malloc(alloc_length);
while (true) {
char* cursor = data + data_length;
char* line = fgets(cursor, alloc_length - data_length, stdin);
if (!line) {
break;
}
data_length += strlen(cursor);
if (data_length < alloc_length - 1 || data[data_length - 1] == '\n') {
break;
}
alloc_length <<= 1;
data = realloc(data, alloc_length);
if (!data) {
data = '\0';
break;
}
}
if (data[data_length - 1] == '\n') {
data[data_length - 1] = '\0';
data = realloc(data, data_length);
if (!data) {
data = '\0';
}
} else {
data = realloc(data, data_length + 1);
if (!data) {
data = '\0';
} else {
data[data_length] = '\0';
}
}
return data;
}
char* ltrim(char* str) {
if (!str) {
return '\0';
}
if (!*str) {
return str;
}
while (*str != '\0' && isspace(*str)) {
str++;
}
return str;
}
char* rtrim(char* str) {
if (!str) {
return '\0';
}
if (!*str) {
return str;
}
char* end = str + strlen(str> - 1;
while (end >= str && isspace(*end)) {
end--;
}
*(end + 1) = '\0';
return str;
}
char** split_string(char* str) {
char** splits = NULL;
char* token = strtok(str, " ");
int spaces = 0;
while (token) {
splits = realloc(splits, sizeof(char*) * ++spaces);
if (!splits) {
return splits;
}
splits[spaces - 1] = token;
token = strtok(NULL, " ");
}
return splits;
}
int parse_int(char* str) {
char* endptr;
int value = strtol(str, &endptr, 10);
if (endptr == str || *endptr != '\0') {
exit(EXIT_FAILURE);
}
return value;
}
#2 Code Example with C++ Programming
Code -
C++ Programming
#include<bits/stdc++.h>
using namespace std;
int main(){
long long int r,c;
cin>>r>>c;
if(r%2!=0)
cout<< (5*(r-1))+((c-1)*2);
else
cout << (5*(r-2))+1+((c-1)*2);
return 0;
}
#3 Code Example with Java Programming
Code -
Java Programming
import java.util.Scanner;
public class Solution {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int row = sc.nextInt(), column = sc.nextInt();
int[] odd_row = {0, 2, 4, 6, 8};
int[] even_row = {1, 3, 5, 7, 9};
long result;
if (row % 2 == 0)
result = 10L * (row / 2 - 1) + even_row[column - 1];
else
result = 10L * (row / 2) + odd_row[column - 1];
System.out.println(result);
}
}
#4 Code Example with Javascript Programming
Code -
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', function(inputStdin) {
inputString += inputStdin;
});
process.stdin.on('end', function() {
inputString = inputString.split('\n');
main();
});
function readLine() {
return inputString[currentLine++];
}
/*
* Complete the 'strangeGrid' function below.
*
* The function is expected to return an INTEGER.
* The function accepts following parameters:
* 1. INTEGER r
* 2. INTEGER c
*/
function strangeGrid(r, c) {
return Math.floor(0.5*r-.5)*10 + (r-1)%2 + 2*c - 2
}
function main() {
const ws = fs.createWriteStream(process.env.OUTPUT_PATH);
const firstMultipleInput = readLine().replace(/\s+$/g, '').split(' ');
const r = parseInt(firstMultipleInput[0], 10);
const c = parseInt(firstMultipleInput[1], 10);
const result = strangeGrid(r, c);
ws.write(result + '\n');
ws.end();
}
#5 Code Example with Python Programming
Code -
Python Programming
#!/bin/python3
import math
import os
import random
import re
import sys
#
# Complete the 'strangeGrid' function below.
#
# The function is expected to return an INTEGER.
# The function accepts following parameters:
# 1. INTEGER r
# 2. INTEGER c
#
def strangeGrid(r, c):
if r % 2 == 0:
return int(5*r+2*c-11)
else:
return int(5*r+2*c-7)
if __name__ == '__main__':
fptr = open(os.environ['OUTPUT_PATH'], 'w')
first_multiple_input = input().rstrip().split()
r = int(first_multiple_input[0])
c = int(first_multiple_input[1])
result = strangeGrid(r, c)
fptr.write(str(result) + '\n')
fptr.close()