78

Author: Ashish-kumar7

78.cpp

@@ -0,0 +1,23 @@
+void solve(vector<int>&nums,vector<int>&temp,vector<vector<int>>&A,int ind){
+    if(ind > nums.size()){
+        return ;
+    }
+    A.push_back(temp);
+    
+    for(int i=ind;i<nums.size();i++){
+        temp.push_back(nums[i]);
+        solve(nums,temp,A,i+1);
+        temp.pop_back();
+    }
+    
+    return ;  
+}
+class Solution {
+public:
+    vector<vector<int>> subsets(vector<int>& nums) {
+        vector<vector<int>>A;
+        vector<int>temp;        
+        solve(nums,temp,A,0);
+        return A;
+    }
+};

New Text Document (2).txt

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int firstUniqChar(string s) {
+        vector<int>A(26,0);
+        for(int i=0;i<s.length();i++){
+            A[s[i]-'a']++;
+        }
+        
+        for(int j=0;j<s.length();j++){
+            if(A[s[j]-'a'] == 1){
+                return j;
+            }
+        }
+        
+        return -1;
+        
+    }
+};

New Text Document.txt

@@ -0,0 +1,26 @@
+class Solution {
+public:
+    int singleNumber(vector<int>& nums) {
+        
+       long long int result=0;
+        int n=nums.size();
+        int bits[32]= {0};
+        
+        for(int i=0;i<32;i++){
+            for(int n:nums){
+                
+                bits[i]+= (n>>i) & 1;
+                bits[i]=bits[i]%3;
+                
+                
+            }
+        }
+        
+        for(int i=0;i<32;i++){
+            result=result+pow(2,i)*bits[i];
+           // cout<<result<<endl;
+        }
+        
+        return result;
+    }
+};

leetcode-com-explore-challenge-card-june-leetcoding-challenge-542-week-4-june-22nd-june-28th-3368.cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int numTrees(int n) {
+        
+        int dp[n+1];
+        dp[0]=dp[1]=1;
+        for(int i=2;i<=n;i++){
+            dp[i]=0;
+            for(int j=1;j<=i;j++){
+                dp[i]+=dp[j-1]*dp[i-j];
+            }
+        }
+        
+        return dp[n];
+        
+    }
+};

leetcode-com-explore-challenge-card-june-leetcoding-challenge-542-week-4-june-22nd-june-28th-3370.cpp

@@ -0,0 +1,20 @@
+class Solution {
+public:
+    int findDuplicate(vector<int>& nums) {
+        int slow=nums[0];
+        int fast=nums[0];
+        
+       do{
+           slow=nums[slow];
+           fast=nums[nums[fast]];
+       }
+        while(slow!=fast);
+        
+        slow=nums[0];
+        while(slow!=fast){
+            fast=nums[fast];
+            slow=nums[slow];
+        }
+        return fast;
+    }
+};

leetcode-com-explore-challenge-card-june-leetcoding-challenge-542-week-4-june-22nd-june-28th-3371.cpp

@@ -0,0 +1,29 @@
+void sumtotal(TreeNode * root , int  value ,int & sum){
+    
+    if(root->left==NULL  && root->right==NULL){
+         sum+=(value*10)+root->val;
+        return ;
+    }
+    value=value*10 + root->val;
+    if(root->left){
+        sumtotal(root->left,value,sum);
+    }
+     if(root->right){
+        sumtotal(root->right,value,sum);
+    }
+    return ;
+}
+
+class Solution {
+public:
+    int sumNumbers(TreeNode* root) {
+        if(root==NULL){
+            return 0;
+        }
+        int value=0;
+        int sum=0;
+        
+        sumtotal(root,value,sum);
+        return sum;
+    }
+};

leetcode-com-explore-challenge-card-june-leetcoding-challenge-542-week-4-june-22nd-june-28th-3372.cpp

@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int numSquares(int n) {
+        int dp[n+1];
+        dp[0]=0;
+        dp[1]=1;
+        for(int i=2;i<=n;i++){
+            dp[i]=INT_MAX;
+        }
+        for(int i=2;i<=n;i++){
+            for(int j=1;j*j<=i;j++){
+                dp[i]= min(dp[i], dp[i-(j*j)] + 1) ;
+            }
+        }
+        return dp[n];
+    }
+};

leetcode-com-explore-challenge-card-june-leetcoding-challenge-542-week-4-june-22nd-june-28th-3373.cpp

@@ -0,0 +1,26 @@
+
+class Solution {
+public:
+    int countNodes(TreeNode* root) {
+        if(root==NULL){
+            return 0;
+        }
+        int left_height=1;
+        TreeNode * left= root->left;
+        while(left!=NULL){
+            left=left->left;
+            left_height++;
+        }
+         int right_height=1;
+        TreeNode * right= root->right;
+        while(right!=NULL){
+            right=right->right;
+            right_height++;
+        }
+        if(right_height==left_height){
+            return pow(2,right_height) -1 ;
+        }
+        
+        return 1 + countNodes(root->left) + countNodes(root->right);         
+    }
+};