Merge pull request #1518 from Sidhant-Gupta/sidhant_prs

Sidhant prs

C-Plus-Plus/other/SortColors-DutchNationalFlag.cpp

@@ -0,0 +1,70 @@
+/*                  
+PROBLEM STATEMENT- https://leetcode.com/problems/sort-colors/
+
+Given an array nums with n objects colored red, white, or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue.
+Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively.
+In simpler words sort an array containing 0,1,2.
+
+Solve the problem with a one-pass algorithm using only O(1) constant space?
+
+The bruteforce approach - Sort the vector in nlogn time
+
+                                ************************DUTCH_NATIONAL_FLAG ALGORITHM***********************************
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+void sortColors(vector<int> nums) {
+        int n=nums.size();
+        int low=0,med=0,high=n-1;
+        int temp;
+        while(med<=high){ 
+            if(nums[med]==0){
+                temp=nums[med];
+                nums[med]=nums[low];
+                nums[low]=temp;
+                low++;
+                med++;
+            }
+            else if(nums[med]==1){
+                med++;
+            }
+            else{
+                temp=nums[med];
+                nums[med]=nums[high];
+                nums[high]=temp;
+                high--;
+            }
+        }
+        for(int i=0;i<n;i++){
+          cout<<nums[i]<<" ";
+        }
+    }
+
+    int main(){
+      vector<int >nums;
+      int n,input;
+      cin>>n;
+      for(int i=0;i<n;i++){
+          cin>>input;
+          nums.push_back(input);
+      }
+      sortColors(nums);
+    }
+
+/*TEST CASE-
+Input:
+n=6
+nums = [2,0,2,1,1,0]
+Output: [0,0,1,1,2,2]
+
+Input:
+n=3
+nums = [2,0,1]
+Output: [0,1,2]
+
+COMPLEXITY ANALYSIS-
+      Time= O(N)
+      space=O(1)
+*/