Commit

Author: rachitvk

Leetcode/LargestSumOfAverages.cpp

@@ -0,0 +1,27 @@
+class Solution {
+public:
+    double largestSumOfAverages(vector<int>& A, int K) {
+        
+        vector<double>P(A.size()+1);
+        vector<double>dp(A.size()+1,0);
+        int n = A.size();
+        
+        for(int i=0;i<n;i++){
+            P[i+1] = P[i]+A[i];
+        }
+        
+        for(int i=0;i<n;i++){
+            dp[i] = (P[n]-P[i])/(n-i);
+        }
+        
+        for(int i=0;i<K-1;i++){
+            for(int j=0;j<n;j++){
+                for(int k=j+1;k<n;k++){
+                    dp[j] = max(dp[j],(P[k]-P[j])/(k-j)+dp[k]);
+                }
+            }
+        }
+        
+        return dp[0];
+    }
+};

Leetcode/LongestArithmeticSubsequence.cpp

@@ -0,0 +1,47 @@
+class Solution {
+public:
+    unordered_map<int,vector<int>>mp;
+    
+    int check(int x,int curr){
+        auto itr = mp[x];
+        
+        for(auto i=itr.begin();i!=itr.end();i++){
+            if(*i>curr){
+                return *i;
+            }
+        }
+        
+        return -1;
+    }
+    
+    int longestArithSeqLength(vector<int>& arr) {
+        
+        for(int i=0;i<arr.size();i++){
+            mp[arr[i]].push_back(i);
+        }
+        
+        int ans = 1;
+        
+        for(int i=0;i<arr.size();i++){
+            for(int j=i+1;j<arr.size();j++){
+                int cnt = 2;
+                int curr = j;
+                int diff = arr[j]-arr[i];
+              
+                
+                while(mp.find(arr[curr]+diff)!=mp.end()){
+                     curr  = check(arr[curr]+diff,curr);
+                     if(curr == -1)
+                         break;
+                     cnt++;
+                }
+             
+                
+                ans = max(ans,cnt);
+            }
+        }
+        
+        return ans;
+
+    }
+};