reversing the array in c++
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/*
An In-place algorithm is an algorithm that does not need an extra space
and produces an output in the same memory that contains the data by
transforming the input ‘in-place’. However, a small constant extra space
used for variables is allowed.
In-place means that the algorithm does not use extra space for manipulating
the input but may require a small though nonconstant extra space for its
operation. Usually, this space is O(log n), though sometimes anything in o(n)
(Smaller than linear) is allowed
Reversing an array in-place and not in-place
*/
/*1st method (not in-place)*/
#include <iostream>
#include <array>
using namespace std;
void reverse_nip(int* arr,int n);
void reverse_ip(int* arr,int n);
int main() {
int arr[5] = {11,22,13,4,1};
int n = sizeof(arr)/sizeof(arr[0]);
reverse_nip(arr,n);
cout << "After reversing the array is: \n";
for(int i=0; i<n; ++i){
cout << arr[i] << "\t";
}
return 0;
}
void reverse_nip(int* arr, int n){
int rev[n];
for(int i=0; i<n; ++i){
rev[i] = arr[n-i-1];
}
for(int i=0; i<n; ++i){
arr[i] = rev[i];
}
return;
}
void reverse_ip(int* arr, int n){
for(int i=0; i<n/2; ++i){
swap(arr[i],arr[n-i-1]);
}
return;
}
Cpp
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