feature: min cost climbing added

Author: Debashis08

include/0005_DynamicProgramming/0004_MinimumCostClimbingStairs.h

@@ -0,0 +1,25 @@
+#pragma once
+#include<vector>
+using namespace std;
+
+/*
+Pattern 1
+Linear Recurrence
+
+Description
+Given an array of integers cost[] of length n, where cost[i] is the cost of the ith step on a staircase. Once the cost is paid, we can either climb 1 or 2 steps.
+We can either start from the step with index 0, or the step with index 1. The task is to find the minimum cost to reach the top.
+
+*/
+
+namespace MinimumCostClimbingStairs
+{
+	class DynamicProgramming
+	{
+	private:
+		int MinCostRecursive(int step, vector<int>& cost);
+	public:
+		int RecursiveMinimumCostClimbingStairs(vector<int>& cost);
+		int DpMinimumCostClimbingStairs(vector<int>& cost);
+	};
+}

source/0005_DynamicProgramming/0004_MinimumCostClimbingStairs.cc

@@ -0,0 +1,48 @@
+#include "../../include/0005_DynamicProgramming/0004_MinimumCostClimbingStairs.h"
+#include<algorithm>
+
+namespace MinimumCostClimbingStairs
+{
+	int DynamicProgramming::MinCostRecursive(int step, vector<int>& cost)
+	{
+		if (step == 0 || step == 1)
+		{
+			return cost[step];
+		}
+
+		return cost[step] + min(this->MinCostRecursive(step - 1, cost), this->MinCostRecursive(step - 2, cost));
+	}
+
+	int DynamicProgramming::RecursiveMinimumCostClimbingStairs(vector<int>& cost)
+	{
+		int totalSteps = cost.size();
+
+		if (totalSteps == 1)
+		{
+			return cost[0];
+		}
+
+		return min(this->MinCostRecursive(totalSteps - 1, cost), this->MinCostRecursive(totalSteps - 2, cost));
+	}
+
+	int DynamicProgramming::DpMinimumCostClimbingStairs(vector<int>& cost)
+	{
+		int totalSteps = cost.size();
+		vector<int> dp(totalSteps, 0);
+
+		if (totalSteps == 1)
+		{
+			return cost[0];
+		}
+
+		dp[0] = cost[0];
+		dp[1] = cost[1];
+
+		for (int i = 2; i < totalSteps; i++)
+		{
+			dp[i] = cost[i] + min(dp[i - 1], dp[i - 2]);
+		}
+
+		return min(dp[totalSteps - 1], dp[totalSteps - 2]);
+	}
+}

source/0005_DynamicProgramming/CMakeLists.txt

@@ -3,6 +3,7 @@ set(0005DYNAMICPROGRAMMING_SOURCES
     0001_FibonacciNumber.cc
     0002_TribonacciNumber.cc
     0003_ClimbingStairs.cc
+    0004_MinimumCostClimbingStairs.cc
 
 )
 

test/0005_DynamicProgramming/0004_MinimumCostClimbingStairsTest.cc

@@ -0,0 +1,33 @@
+#include<gtest/gtest.h>
+#include "../../include/0005_DynamicProgramming/0004_MinimumCostClimbingStairs.h"
+
+namespace MinimumCostClimbingStairs
+{
+	TEST(MinimumCostClimbingStairs, RecursionTest)
+	{
+		// Arrange
+		DynamicProgramming dp;
+		vector<int> cost = { 16, 19, 10, 12, 18 };
+		int expectedCost = 31;
+
+		// Act
+		int actualCost = dp.RecursiveMinimumCostClimbingStairs(cost);
+
+		// Assert
+		ASSERT_EQ(expectedCost, actualCost);
+	}
+
+	TEST(MinimumCostClimbingStairs, DpTest)
+	{
+		// Arrange
+		DynamicProgramming dp;
+		vector<int> cost = { 16, 19, 10, 12, 18 };
+		int expectedCost = 31;
+
+		// Act
+		int actualCost = dp.DpMinimumCostClimbingStairs(cost);
+
+		// Assert
+		ASSERT_EQ(expectedCost, actualCost);
+	}
+}

test/0005_DynamicProgramming/CMakeLists.txt

@@ -17,6 +17,7 @@ add_executable(
   0001_FibonacciNumberTest.cc
   0002_TribonacciNumberTest.cc
   0003_ClimbingStairsTest.cc
+  0004_MinimumCostClimbingStairsTest.cc
 
 )