904. Increase by 2

The sequence of integers is given. Increase each its non-negative element by 2.

Input. The first line contains the number of elements n (n ≤ 100). The second line contains the sequence of integers, with each element not exceeding 100 in absolute value.

Output. Print n integers in a single line – the new elements of the sequence, in their original order.

Sample Input	Sample Output
4 1 2 3 -4	3 4 5 -4

SOLUTION

loops

Algorithm analysis

The problem can be solved both with and without an array. Sequentially read the numbers and increment each non-negative element by 2.

Algorithm implementation

Read the input value of n.

scanf("%d",&n);

Sequentially read n integers.

for (i = 0; i < n; i++)

{

scanf("%d",&val);

If the number val is non-negative, increase it by 2.

if (val >= 0) val +=2;

Print the number val after the modification.

printf("%d ",val);

}

printf("\n");

Algorithm implementation – array

Declare an array.

int m[101];

Read the input data.

scanf("%d",&n);

for (i = 0; i < n; i++)

scanf("%d",&m[i]);

Iterate through the elements of an array. Increase each non-negative element by 2.

for (i = 0; i < n; i++)

if (m[i] >= 0) m[i] = m[i] + 2;

Print the answer – the resulting array.

for (i = 0; i < n; i++)

printf("%d ",m[i]);

printf("\n");

Algorithm implementation – vector, push_back

Read the input data.

scanf("%d",&n);

for (i = 0; i < n; i++)

{

scanf("%d",&val);

m.push_back(val);

}

Iterate through the elements of an array. Increase each non-negative element by 2.

for (i = 0; i < n; i++)

if (m[i] >= 0) m[i] = m[i] + 2;

Print the answer – the resulting array.

for (i = 0; i < n; i++)

printf("%d ",m[i]);

printf("\n");

Algorithm implementation – vector, resize

Read the input data.

scanf("%d",&n);

m.resize(n);

for (i = 0; i < n; i++)

scanf("%d",&m[i]);

Iterate through the elements of an array. Increase each non-negative element by 2.

for (i = 0; i < n; i++)

if (m[i] >= 0) m[i] = m[i] + 2;

Print the answer – the resulting array.

for (i = 0; i < n; i++)

printf("%d ",m[i]);

printf("\n");

Algorithm implementation – pointers

#include <stdio.h>

int i, n;

int *m;

int main(void)

{

scanf("%d",&n);

// allocate mamory

m = new int[n];

// read the array

for (i = 0; i < n; i++)

scanf("%d",&m[i]);

// process the array

for (i = 0; i < n; i++)

if (m[i] >= 0) m[i] = m[i] + 2;

// print the array

for (i = 0; i < n; i++)

printf("%d ",m[i]);

printf("\n");

// free the memory

delete[] m;

return 0;

}

Java implementation

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

int n = con.nextInt();

for (int i = 0; i < n; i++)

{

int val = con.nextInt();

if (val >= 0) val += 2;

System.out.print(val + " ");

}

System.out.println();

con.close();

}

}

Java implementation – array

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

int n = con.nextInt();

int m[] = new int[n];

for (int i = 0; i < n; i++)

m[i] = con.nextInt();

for (int i = 0; i < n; i++)

if (m[i] >= 0) m[i] += 2;

for (int i = 0; i < n; i++)

System.out.print(m[i] + " ");

System.out.println();

con.close();

}

}

Java implementation – ArrayList

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

int n = con.nextInt();

ArrayList<Integer> m = new ArrayList<Integer>();

for (int i = 0; i < n; i++)

{

int val = con.nextInt();

m.add(val);

}

for (int i = 0; i < n; i++)

if (m.get(i) >= 0) m.set(i,m.get(i)+2);

for (int i = 0; i < n; i++)

System.out.print(m.get(i) + " ");

System.out.println();

con.close();

}

}

Python implementation

Read the input data.

n = int(input())

lst = list(map(int,input().split()))

Iterate through the elements of a list. Increase each non-negative element by 2.

for i in range(n):

if lst[i] >= 0:

lst[i] = lst[i] + 2

Print the answer – the list lst.

print(*lst)

Python implementation – create a list

Read the input data.

n = int(input())

list = list(map(int,input().split()))

Create the resulting list p. Increase each non-negative element of the list lst by 2.

p = [x + 2 if x >= 0 else x for x in lst]

Print the answer.

print(*p)

Python implementation – map

Read the input data.

n = int(input())

lst = map(int,input().split())

Declare a function f defined as follows:

f(n) =

def f(n):

if n >= 0:

return n + 2

return n

Apply the function f to each element of the list lst.

res = list(map(f,lst))

Print the list res.

for x in res:

print(x, end=" ")