Merge pull request #1 from rakshaa2000/patch-1

Patch 1

greedy_algorithms/jumpgame.cpp

@@ -0,0 +1,40 @@
+/**
+ * @file
+ * \brief Implementation of an algorithm to solve the jumping game problem
+ * \details
+ * This algorithm is a greedy algorithm.
+ * This solution takes in input as a vector and output as a boolean to check if you can reach the last position.
+ * @author 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>
+
+//Implements the algorithm
+/*We name the indices good and bad based on whether we can reach the destination if we start at that position.
+ *We initialize the last index as lastPos.
+ *Here, we start from the end of the array and check if we can ever reach the first index.
+ *We check if the sum of the index and the maximum jump count given is greater than or equal to the lastPos.
+ *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.
+*/
+bool canJump(std::vector<int> nums) {
+    auto lastPos = nums.size() - 1;
+    for (auto i = nums.size() - 1; i >= 0; i--) {
+        if (i + nums[i] >= lastPos) {
+            lastPos = i;
+        }
+    }
+    return lastPos == 0;
+}
+
+int main(){
+    //Sample test case
+    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;
+}