1 files changed, 32 insertions, 0 deletions
diff --git a/datastructures/segmentTree.cpp b/datastructures/segmentTree.cpp
new file mode 100644
index 0000000..6b73ec0
--- /dev/null
+++ b/datastructures/segmentTree.cpp
@@ -0,0 +1,32 @@
+int a[MAX_N], m[4 * MAX_N];
+
+int query(int x, int y, int k = 0, int X = 0, int Y = MAX_N - 1) {
+	if (x <= X && Y <= y) return m[k];
+	if (y < X || Y < x) return -1000000000; //ein "neutrales" Element
+	int M = (X + Y) / 2;
+	return max(query(x, y, 2 * k + 1, X, M), query(x, y, 2 * k + 2, M + 1, Y));
+}
+
+void update(int i, int v, int k = 0, int X = 0, int Y = MAX_N - 1) {
+	if (i < X || Y < i) return;
+	if (X == Y) {
+		m[k] = w;
+		a[i] = w;
+		return;
+	}
+	int M = (X + Y) / 2;
+	update(i, v, 2 * k + 1, X, M);
+	update(i, v, 2 * k + 2, M + 1, Y);
+	m[k] = max(m[2 * k + 1], m[2 * k + 2]);
+}
+
+void init(int k = 0, int X = 0, int Y = MAX_N - 1) {
+	if (X == Y) {
+		m[k] = a[X];
+		return;
+	}
+	int M = (X + Y) / 2;
+	init(2 * k + 1, X, M);
+	init(2 * k + 2, M + 1, Y);
+	m[k] = max(m[2 * k + 1], m[2 * k + 2]);
+}
+\ No newline at end of file