Top 10

Author: CodeRex7

geekforgeeks/Top 10 Algorithms/Array/PallindromeString.cpp

@@ -0,0 +1,54 @@
+/*
+*	Given a string, print all possible palindromic partitions
+*/
+
+#include<bits/stdc++.h>
+#define pb push_back
+#define pob pop_back
+using namespace std;
+
+bool isPallin(string s, int l, int h){
+	while(l<h){
+		if(s[l]!=s[h])
+			return false;
+		l++;
+		h--;
+	}
+	return true;
+}
+
+void allPalPartion(vector< vector<string> >&allPal, vector<string>&currPal, int start, int end, string str){
+	if(start>=end)	
+	{
+		allPal.pb(currPal);
+		return;
+	}
+
+	for(int i=start;i<end;i++){
+		if(isPallin(str,start,i))
+		{
+			currPal.pb(str.substr(start,i-start+1));
+			allPalPartion(allPal,currPal,i+1,end,str);
+			currPal.pob();
+		}
+	}
+}
+
+int main()
+{
+	string str;
+	cin>>str;
+
+	vector< vector<string> >allPal;
+	vector<string>currPal;
+
+	allPalPartion(allPal, currPal, 0, str.size(), str);
+
+	for(int i=0;i<allPal.size();i++)
+	{
+		for (int j=0; j<allPal[i].size(); j++)
+            cout << allPal[i][j] << " ";
+        cout << "\n";
+	}
+	return 0;
+}

geekforgeeks/Top 10 Algorithms/Array/a.out

@@ -0,0 +1,34 @@
+/*
+*	Reverse an array without affecting special characters
+*/
+
+#include<bits/stdc++.h>
+using namespace std;
+
+bool isAlphabet(char ch){
+	if((ch>='A' && ch<='Z')||(ch>='a' && ch<='z'))
+		return true;
+	return false;	
+}
+
+int main()
+{
+	string s;
+	cin>>s;
+
+	int l=0;
+	int r=s.size()-1;
+
+	while(l<r){
+		if(!isAlphabet(s[l]))
+			l++;
+		else if(!isAlphabet(s[r]))
+			r--;
+		else{
+			swap(s[l],s[r]);
+			l++;
+			r--;
+		}
+	}
+	cout<<s<<endl;
+}

geekforgeeks/Top 10 Algorithms/Array/reverse.cpp

@@ -0,0 +1,39 @@
+/*
+*	Count triplets with sum smaller than a given value
+*/
+
+#include<bits/stdc++.h>
+#define pb push_back
+using namespace std;
+
+
+int countTriplets(vector<int> arr,int sum){
+	int ans=0;
+	int n=arr.size();
+	for(int i=0;i<n-2;i++){
+		int l=i+1,h=n-1;
+		while(l<h){
+			if(arr[i]+arr[l]+arr[h]>=sum)
+				h--;
+			else{
+				ans+=(h-l);//these many possible triplets can be formed with same i,l and varying h.
+				l++;
+			}
+		}
+	}
+	return ans;
+}
+
+int main(){
+	int n,sum;
+	cin>>n>>sum;
+	vector<int>arr;
+	for(int i=0;i<n;i++)
+	{
+		int a;
+		cin>>a;
+		arr.push_back(a);
+	}
+	sort(arr.begin(), arr.end());
+	cout<<countTriplets(arr,sum)<<endl;
+}