Create 29 November Count the Number of Full Binary Trees

29 November Count the Number of Full Binary Trees

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+class Solution{
+public:
+   long long int numoffbt(long long int arr[], int n){
+
+
+
+        const long long int MOD = 1000000007;
+
+
+
+        long long int mn = INT_MAX, mx = INT_MIN;
+
+
+
+        for(int i = 0; i < n; i++){
+
+
+
+            mn = (mn > arr[i]) ? arr[i] : mn;
+
+
+
+            mx = (mx < arr[i]) ? arr[i] : mx;
+
+
+
+        }
+
+
+
+
+
+
+
+        long long int ans = 0;
+
+
+
+        int pd;
+
+
+
+        vector<bool> vis(mx+1, false);
+
+
+
+        vector<long long int> sol(mx+1, 0);
+
+
+
+        for(int i = 0; i < n; i++){
+
+
+
+            vis[arr[i]] = 1;
+
+
+
+            sol[arr[i]] = 1;
+
+
+
+        }
+
+
+
+        for(int i = mn; i <= mx; i++){
+
+
+
+            if(!vis[i]){
+
+
+
+                continue;
+
+
+
+            }
+
+
+
+            for(int j = 2; i*j <= mx && j <= i; j++){
+
+
+
+                pd = i*j;
+
+
+
+                if(!vis[pd]){
+
+
+
+                    continue;
+
+
+
+                }
+
+
+
+                sol[pd] = (sol[pd] + (sol[i]*sol[j])%MOD)%MOD;
+
+
+
+                if(i != j){
+
+
+
+                    sol[pd] = ( sol[pd] + (sol[i]*sol[j])%MOD)%MOD;
+
+
+
+                }
+
+
+
+            }
+
+
+
+            ans = (ans + sol[i])%MOD;
+
+
+
+        }
+
+
+
+        return ans;
+
+
+
+    }
+
+};