weighted interval scheduling problem

DAA_Weighted_Interval_Scheduling.cpp

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+#include<iostream>
+using namespace std;
+#define MAX 20
+int M[MAX];
+struct Interval
+{
+	int start_time, finish_time, weight;
+};
+class WIS
+{
+	Interval I[MAX];
+public:
+	int n;
+	WIS()
+	{
+		for (int i = 0; i <= MAX; i++)
+			M[i] = 0;
+	}
+	int input();
+	void interval_sort();
+	int z(int); //getting finished and non-overlapping intervals
+	int m_compute_opt(int);
+};
+int WIS::z(int j)
+{
+	for (int i = j - 1; i > 0; i--)
+	{
+		if (I[i].finish_time <= I[j].start_time)
+		{
+			return i;
+		}
+	}
+	return 0;
+}
+int WIS::input()
+{
+	cout << "\nEnter number of intervals: ";
+	cin >> n;
+	cout << "\nEnter the starting time, finishing time and weight value of intervals: ";
+	cout << "\n\nSi "<<" Fi "<<" Vi\n";
+	for (int i = 1; i <= n; i++)
+	{
+		cin >> I[i].start_time;
+		cin >> I[i].finish_time;
+		cin >> I[i].weight;
+	}
+}
+void WIS::interval_sort()
+{
+	int i, flag = 1;
+	Interval temp;
+	for (i = 1; (i <= n) && flag; i++)
+	{
+		flag = 0;
+		for (int j = 1; j < n; j++)
+		{
+			if (I[j+1].finish_time < I[j].finish_time)
+			{
+				temp = I[j];
+				I[j] = I[j + 1];
+				I[j + 1] = temp;
+				flag = 1;
+			}
+		}
+	}
+	for (i = 1; i <= n; i++)
+	{
+		for (int j = i + 1; j <= n; j++)
+		{
+			if (I[i].finish_time == I[j].finish_time && I[i].start_time > I[j].start_time)
+			{
+				temp = I[i];
+				I[i] = I[j];
+				I[j] = temp;
+			}
+		}
+	}
+	cout << "I<i>\t\tS<i>\t\tF<i>\t\tV<i>\n";
+	for (int i = 1; i <= n; i++)
+	{
+		cout << i << "\t\t" << I[i].start_time << "\t\t" << I[i].finish_time << "\t\t" << I[i].weight << "\n";
+	}
+}
+int WIS::m_compute_opt(int j)
+{
+	if (j == 0)
+	{
+		return 0;
+	}
+	else if (M[j])
+	{
+		return M[j];
+	}
+	else
+	{
+		M[j] = max((I[j].weight + m_compute_opt(z(j))),m_compute_opt(j - 1));
+	}
+	return M[j];
+}
+int main()
+{
+	WIS job;
+	job.input();
+	cout << "\nSorted Input Intervals: \n";
+	job.interval_sort();
+	cout << endl;
+	for (int i = 1; i <= job.n; i++)
+		cout << "OPT[" << i << "]\t";
+	cout << endl;
+	for (int i = 1; i <= job.n; i++)
+		cout << job.m_compute_opt(i) << "\t";
+	return 0;
+}
+