Create 2183.Count-Array-Pairs-Divisible-by-K.cpp

cc98mengxinghun · Feb 21, 2022 · ccb314e · ccb314e
1 parent cc3ffaa
commit ccb314e
Showing 1 changed file with 34 additions and 0 deletions.
diff --git a/Math/2183.Count-Array-Pairs-Divisible-by-K/2183.Count-Array-Pairs-Divisible-by-K.cpp b/Math/2183.Count-Array-Pairs-Divisible-by-K/2183.Count-Array-Pairs-Divisible-by-K.cpp
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+class Solution {
+public:
+    long long countPairs(vector<int>& nums, int k) 
+    {
+        unordered_set<int>yueshu;
+        for (int i=1; i*i<=k; i++)
+        {
+            if (k%i!=0) continue;
+            yueshu.insert(i);
+            if (i*i!=k)
+                yueshu.insert(k/i);
+        }
+
+        unordered_map<int, vector<int>>Map;
+        for (int i=0; i<nums.size(); i++)
+            for (auto x: yueshu)
+            {
+                if (nums[i]%x==0)
+                    Map[x].push_back(i);
+            }
+
+        long long ret = 0;
+        for (int i=0; i<nums.size(); i++)
+        {
+            int a = gcd(nums[i], k);
+            int b = k/a;
+            auto iter = upper_bound(Map[b].begin(), Map[b].end(), i);
+            ret += Map[b].end() - iter;
+        }
+
+        return ret;
+
+    }
+};