add greedy activity

1 files changed, 66 insertions, 0 deletions

diff --git a/Year_2/Algorithms/greedy-activity.cc b/Year_2/Algorithms/greedy-activity.cc
new file mode 100644
index 0000000..3c3a9e4
--- /dev/null
+++ b/Year_2/Algorithms/greedy-activity.cc
@@ -0,0 +1,66 @@
+#include <iostream>
+#include <fstream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+typedef pair<int, int> pii;
+
+void
+activity(vector<pii> v, ostream& out)
+{
+	int n = v.size();
+	int c = 0;
+	for (int i = 0; i < n; ++i) {
+		for (int k = i+1; k < n; ++k) {
+			int pivot = v[i].second;
+			int lc = 1;
+			for (int j = k; j < n; ++j) {
+				if (v[j].first >= pivot) {
+					lc++;
+					pivot = v[j].second;
+				}
+			}
+
+			c = max(c, lc);
+		}
+	}
+
+	out << c << endl;
+}
+
+int
+main(int argc, char** argv)
+{
+	int ts = (argc > 1) ? stoi(argv[1]) : 100;
+	ifstream fin("input.txt");
+	ofstream fout("output.txt");
+	int n;
+	string s;
+	int x1, x2;
+
+	for (int i = 0; i < ts; ++i) {
+		fin >> n;
+		vector<pii> v;
+
+		for (int j = 0; j < n; ++j) {
+			fin >> s;
+			x1 = stoi(s.substr(1, s.length()));
+			fin >> s;
+			x2 = stoi(s.substr(0, s.length()-1));
+			v.push_back({x1, x2});
+		}
+
+		sort(v.begin(), v.end(), [] (pii x1, pii x2) {
+			return x1.second < x2.second;
+		});
+
+		activity(v, fout);
+	}
+
+	fin.close();
+	fout.close();
+
+	return 0;
+}