Merge pull request #4 from rakshaa2000/master

More documentation and testing

DIRECTORY.md

@@ -58,7 +58,6 @@
   * [Edit Distance](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/edit_distance.cpp)
   * [Egg Dropping Puzzle](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/egg_dropping_puzzle.cpp)
   * [Fibonacci Bottom Up](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/fibonacci_bottom_up.cpp)
-  * [Fibonacci Top Down](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/fibonacci_top_down.cpp)
   * [Floyd Warshall](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/floyd_warshall.cpp)
   * [Kadane](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/kadane.cpp)
   * [Longest Common String](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/longest_common_string.cpp)

data_structures/linked_list_delete_without_head.cpp

@@ -0,0 +1,109 @@
+/**
+ * @file
+ * \brief Delete a node in a linked list without the head pointer
+ * \details
+ * This algortihm helps delete a node in a linked list without the access of a head pointer
+ * @author rakshaa2000
+*/
+
+//Delete without a head pointer.
+/*You are given a pointer/ reference to the node which is to be deleted from the linked list of N nodes. The task is to delete the node. Pointer/ reference to head node is not given. 
+Note: No head reference is given to you.*/
+
+/*
+Example 1:
+
+Input:
+N = 3
+value[] = {1,2,3}
+node = 1
+Output: 2 3
+Explanation: After deleting 1 from the
+linked list, we have remaining nodes
+as 2 and 3.
+
+Example 2:
+
+Input:
+N = 4
+value[] = {70,20,60,30}
+node = 20
+Output: 40 60 30
+Explanation: After deleting 20 from
+the linked list, we have remaining
+nodes as 40, 60 and 30.
+
+*/
+
+#include <iostream>
+//Driver Code starts
+//Linked list node structure
+struct Node{
+  int data;
+  Node *next;
+  explicit Node(int x){
+    data=x;
+    next=nullptr;
+  }
+} *head;
+
+//To search for the given node
+Node *findNode(Node *head, int search){
+  Node *cur= head;
+  while(cur!=nullptr){
+    if(cur->data==search)
+      break;
+    cur=cur->next;
+  }
+}
+
+//To populate the linked list
+void insert(){
+  int i=0, n, value;
+  Node *temp;
+  scanf("%d",&n);
+  for(int i=0; i<n; i++){
+    scanf("%d", &value);
+    if(i==0){
+      head= new Node(value);
+      temp=head;
+      continue;
+    }
+    else{
+      temp->next=new Node(value);
+      temp=temp->next;
+      new Node(value);
+      temp->next=NULL;
+    }
+  }
+}
+
+//To print the entire list
+void printList (Node *node){
+  while(node!=NULL){
+    printf("%d",node->data);
+    node=node->next;
+  }
+  std::cout<<endl;
+}
+
+//Driver Code Ends
+
+//Function to locate the node to be deleted
+void deleteNode(Node *m)
+{
+   *m=*m->next;
+}
+
+//Main function
+int main(){
+  int k;
+  insert();
+  scanf("%d",&k);
+  Node *del= findNode(head,k);
+  if(del!=NULL && del->next!=NULL){
+    deleteNode(del);
+  }
+  printList(head);
+  return 0;
+}

dynamic_programming/fibonacci_top_down.cpp

@@ -1,22 +0,0 @@
-#include <iostream>
-using namespace std;
-int arr[1000000];
-int fib(int n) {
-    if (arr[n] == -1) {
-        if (n <= 1)
-            arr[n] = n;
-        else
-            arr[n] = fib(n - 1) + fib(n - 2);
-    }
-    return arr[n];
-}
-int main(int argc, char const *argv[]) {
-    int n;
-    cout << "Enter n: ";
-    cin >> n;
-    for (int i = 0; i < n + 1; ++i) {
-        arr[i] = -1;
-    }
-    cout << "Fibonacci number is " << fib(n) << endl;
-    return 0;
-}

greedy_algorithms/jumpgame.cpp

@@ -6,13 +6,10 @@
  * This solution takes in input as a vector and output as a boolean to check if you can reach the last position.
  * @author [Rakshaa Viswanathan](https://github.com/rakshaa2000)
 */
-//Jump Game:
-/*Given an array of non-negative integers, you are initially positioned at the first index of the array.
-Each element in the array represents your maximum jump length at that position.
-Determine if you are able to reach the last index.*/
 
 #include <vector>
 #include<iostream>
+#include <cassert>
 
 //Implements the algorithm
 /*We name the indices good and bad based on whether we can reach the destination if we start at that position.
@@ -22,6 +19,11 @@ Determine if you are able to reach the last index.*/
  *If yes, then that is the last position you can reach starting from the back.
  *After the end of the loop, if we reach the lastPos as 0, then the destination can be reached from the start position.
 */
+ /**
+ * @brief This function implements the above algorithm
+ * @param vector of nums containing the maximum jump (in steps) from that index
+ * @return returns bool value whether final index can be reached or not
+ */  
 bool canJump(std::vector<int> nums) {
     auto lastPos = nums.size() - 1;
     for (auto i = nums.size() - 1; i >= 0; i--) {
@@ -32,13 +34,35 @@ bool canJump(std::vector<int> nums) {
     return lastPos == 0;
 }
 
+
+/**
+ * @brief Function to test above algorithm
+ */
+void test(){
+  //Test 1
+  std::vector<int> num1={4,3,1,0,5};
+  assert(canJump(num1)==true);
+  std::cout<<"Input: ";
+  for(auto i: num1){
+    std::cout<<i<<" ";
+  }
+  std::cout<<"Output: true"<<std::endl;
+  //Test 2
+  std::vector<int> num2={3,2,1,0,4};
+  assert(canJump(num2)==false);
+  std::cout<<"Input: ";
+  for(auto i: num2){
+    std::cout<<i<<" ";
+  }
+  std::cout<<"Output: false"<<std::endl;
+}
+
+
 /**
  * @brief Main function
  * @returns 0 on exit
  */
 int main(){
-    //Sample test case
+    test();
-    std::vector<int> num={4,3,1,0,5};
-    std::cout<<canJump(num);  //Should display true, as when you take one step from position 0, you reach position 1, from which 3 steps lead you to the destination
     return 0;
 }