Segregate Negative 2 Pointer

C++/segregateAllNegative.cpp

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+// Problem Statement -  Move all negative numbers to beginning and positive to end with constant extra space
+
+// An array contains both positive and negative numbers in random order. Rearrange the array elements so that all negative numbers appear before all positive numbers.
+
+// Examples : 
+
+// Input: -12, 11, -13, -5, 6, -7, 5, -3, -6
+// Output: -12 -13 -5 -7 -3 -6 11 6 5
+// Note: Order of elements is not important here.
+#include<bits/stdc++.h>
+using namespace std;
+void swap(int arr[],int left,int right){
+    // function to swap two locations in the array
+
+    int temp;
+    temp=arr[right];
+    arr[right]=arr[left];
+    arr[left]=temp;
+    return;
+}
+// the algorithm is inspired from dutch national flag algorithm 
+int main(){
+    int n;
+    cin>>n;
+    int arr[n];
+    for(int i=0;i<n;i++){
+        cin>>arr[i];
+    }
+    int left=0,right=n-1; // two pointers is used ,left to  mark the limit of all negative numbers and right to  mark the unknown numbers
+    while(left<=right){
+        if(arr[left]<0)
+        left++; // if left is negative simply increment left else else swap with right 
+        else
+        {
+            swap(arr,left,right);
+            right--;
+        }
+    }
+    for(int i=0;i<n;i++)
+    cout<<arr[i]<<" "; // finally print the array element 
+    cout<<endl;
+    return 0;
+}