From f4d19062f29640a4da50fc1e9b08b898dc4fea61 Mon Sep 17 00:00:00 2001
From: goo-gy <lkukh17@naver.com>
Date: Fri, 14 Jan 2022 15:08:08 +0900
Subject: [PATCH] Index Tree #1

---
 Algorithm/indexTree.cpp | 64 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 Algorithm/indexTree.cpp

diff --git a/Algorithm/indexTree.cpp b/Algorithm/indexTree.cpp
new file mode 100644
index 0000000..64bbcec
--- /dev/null
+++ b/Algorithm/indexTree.cpp
@@ -0,0 +1,64 @@
+#include <vector>
+
+using namespace std;
+
+class IndexTree
+{
+public:
+    int leafLeft;
+    int treeSize;
+    vector<long long> v_tree;
+    IndexTree(int N)
+    {
+        for (leafLeft = 1; leafLeft < N; leafLeft *= 2)
+            ;
+        treeSize = leafLeft * 2;
+        v_tree.resize(treeSize);
+    }
+
+    long long logicFun(long long num1, long long num2)
+    {
+        // TODO : set logic
+        return num1 + num2;
+    }
+
+    void updateTree(int index)
+    {
+        if (index == 0)
+            return;
+        v_tree[index] = logicFun(v_tree[2 * index], v_tree[2 * index + 1]);
+        updateTree(index / 2);
+    }
+
+    void update(int order, long long data)
+    {
+        int index = leafLeft + order - 1;
+        v_tree[index] = data;
+        updateTree(index / 2);
+    }
+
+    long long query(int begin, int end)
+    {
+        int L = leafLeft + begin - 1;
+        int R = leafLeft + end - 1;
+
+        // TODO: set initial
+        long long result = 0;
+        while (L < R)
+        {
+            int nextL = (L + 1) / 2;
+            int nextR = (R - 1) / 2;
+
+            if (nextL != L / 2)
+                result = logicFun(result, v_tree[L]);
+            if (nextR != R / 2)
+                result = logicFun(result, v_tree[R]);
+
+            L = nextL;
+            R = nextR;
+        }
+        if (L == R)
+            result = logicFun(result, v_tree[L]);
+        return result;
+    }
+};