Create Implement a segment tree for range queries

Implement a segment tree for range queries

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+class SegmentTree:
+    def __init__(self, arr):
+        self.n = len(arr)
+        self.tree = [0] * (4 * self.n)
+        self.build_tree(arr, 0, 0, self.n - 1)
+
+    def build_tree(self, arr, idx, left, right):
+        if left == right:
+            self.tree[idx] = arr[left]
+        else:
+            mid = (left + right) // 2
+            self.build_tree(arr, 2 * idx + 1, left, mid)
+            self.build_tree(arr, 2 * idx + 2, mid + 1, right)
+            self.tree[idx] = min(self.tree[2 * idx + 1], self.tree[2 * idx + 2])
+
+    def query(self, idx, left, right, ql, qr):
+        if ql <= left and right <= qr:  # The segment is fully inside the query range
+            return self.tree[idx]
+        if right < ql or left > qr:  # The segment is fully outside the query range
+            return float('inf')
+        mid = (left + right) // 2
+        left_min = self.query(2 * idx + 1, left, mid, ql, qr)
+        right_min = self.query(2 * idx + 2, mid + 1, right, ql, qr)
+        return min(left_min, right_min)
+
+    def range_query(self, ql, qr):
+        if ql < 0 or qr >= self.n or ql > qr:
+            return float('inf')  # Invalid query range
+        return self.query(0, 0, self.n - 1, ql, qr)
+
+    def update(self, idx, left, right, pos, new_val):
+        if left == right:
+            self.tree[idx] = new_val
+        else:
+            mid = (left + right) // 2
+            if pos <= mid:
+                self.update(2 * idx + 1, left, mid, pos, new_val)
+            else:
+                self.update(2 * idx + 2, mid + 1, right, pos, new_val)
+            self.tree[idx] = min(self.tree[2 * idx + 1], self.tree[2 * idx + 2])
+
+    def point_update(self, pos, new_val):
+        if 0 <= pos < self.n:
+            self.update(0, 0, self.n - 1, pos, new_val)
+
+# Example usage:
+arr = [1, 3, 2, 4, 6, 5, 8, 7]
+segment_tree = SegmentTree(arr)
+
+print("Range Minimum Queries:")
+print(segment_tree.range_query(0, 3))  # Output: 1 (Minimum in range [0, 3])
+print(segment_tree.range_query(2, 5))  # Output: 2 (Minimum in range [2, 5])
+print(segment_tree.range_query(1, 6))  # Output: 2 (Minimum in range [1, 6])
+
+segment_tree.point_update(3, 0)  # Update element at index 3 to 0
+print("After Point Update:")
+print(segment_tree.range_query(0, 3))  # Output: 0 (Minimum in range [0, 3])