Time: 26 ms (19.81%), Space: 157.3 MB (8.56%) - LeetHub

Author: knockcat

0650-2-keys-keyboard/0650-2-keys-keyboard.cpp

@@ -0,0 +1,35 @@
+class Solution {
+public:
+
+    int helper(int n, int last, int tot, vector<vector<int>>& dp)
+    {
+        if(n < 0)
+            return 1e9;
+        
+        if(n == 0)
+            return 0;
+        
+        if(dp[n][last] != -1)
+            return dp[n][last];
+        
+        int previousCopy = 1 + helper(n - last, last, tot, dp);
+        
+        int alreadyTaken = tot - n;
+        
+        int newCopy =  2 + helper(n - alreadyTaken, alreadyTaken, tot, dp);
+        
+        return dp[n][last] = min(newCopy, previousCopy);
+        
+    }
+    
+    int minSteps(int n) {
+        
+        if(n == 1)
+            return 0;
+        
+        vector<vector<int>> dp(n+1,vector<int>(n+1, -1));
+        
+        return helper(n-1, 1, n, dp) + 1;
+        
+    }
+};