Create 1649.Create-Sorted-Array-through-Instructions_v2.cpp

Author: wisdompeak

Divide_Conquer/1649.Create-Sorted-Array-through-Instructions/1649.Create-Sorted-Array-through-Instructions_v2.cpp

@@ -0,0 +1,48 @@
+const int MAX_N = 100000;
+
+class Solution {
+public:    
+    long long bitArr[MAX_N+1];
+    long long nums[MAX_N+1];
+    long long M = 1e9+7;
+
+    void updateDelta(int i, long long delta) {
+        int idx = i;
+        while (idx <= MAX_N)
+        {
+            bitArr[idx]+=delta;
+            bitArr[idx] %= M;
+            idx+=idx&(-idx);
+        }
+    }
+
+    long long queryPreSum(int idx){
+        long long result = 0;
+        while (idx){
+            result += bitArr[idx];
+            result %= M;
+            idx-=idx&(-idx);
+        }
+        return result;
+    }
+
+    long long sumRange(int i, int j) {
+        return queryPreSum(j)-queryPreSum(i-1);
+    }
+    
+    int createSortedArray(vector<int>& instructions) 
+    {        
+        long long ret = 0;
+        
+        for (auto x:instructions)
+        {
+            updateDelta(x, 1);
+            long long a = sumRange(1, x-1);
+            long long b = sumRange(x+1, MAX_N);
+            ret += min(a,b);
+            ret %= M;
+        }
+        return ret;
+        
+    }
+};