Segment_tree with lazy propagation for range sum problem.

data_structures/segment_tree/C++/segment_Tree_with_lazyprop.cpp

@@ -0,0 +1,138 @@
+#include<bits/stdc++.h>
+#define MAX 1000 
+using namespace std;
+int tree[MAX] = {0}; // To store segment tree 
+int lazy[MAX] = {0}; // To store pending updates 
+
+void updateRangeUtil(int si, int ss, int se, int us, 
+					int ue, int diff) 
+{ 
+	if (lazy[si] != 0) 
+	{ 
+		tree[si] += (se-ss+1)*lazy[si]; 
+
+		if (ss != se) 
+		{  
+			lazy[si*2 + 1] += lazy[si]; 
+			lazy[si*2 + 2] += lazy[si]; 
+		} 
+		lazy[si] = 0; 
+	} 
+
+	if (ss>se || ss>ue || se<us) 
+		return ; 
+	if (ss>=us && se<=ue) 
+	{  
+		tree[si] += (se-ss+1)*diff; 
+		if (ss != se) 
+		{ 
+			lazy[si*2 + 1] += diff; 
+			lazy[si*2 + 2] += diff; 
+		} 
+		return; 
+	} 
+
+	int mid = (ss+se)/2; 
+	updateRangeUtil(si*2+1, ss, mid, us, ue, diff); 
+	updateRangeUtil(si*2+2, mid+1, se, us, ue, diff); 
+	tree[si] = tree[si*2+1] + tree[si*2+2]; 
+} 
+
+void updateRange(int n, int us, int ue, int diff) 
+{ 
+updateRangeUtil(0, 0, n-1, us, ue, diff); 
+} 
+
+int getSumUtil(int ss, int se, int qs, int qe, int si) 
+{ 
+	if (lazy[si] != 0) 
+	{ 
+		tree[si] += (se-ss+1)*lazy[si]; 
+		if (ss != se) 
+		{ 
+			// Since we are not yet updating children os si, 
+			// we need to set lazy values for the children 
+			lazy[si*2+1] += lazy[si]; 
+			lazy[si*2+2] += lazy[si]; 
+		} 
+
+		// unset the lazy value for current node as it has 
+		// been updated 
+		lazy[si] = 0; 
+	} 
+	if (ss>se || ss>qe || se<qs) 
+		return 0; 
+	if (ss>=qs && se<=qe) 
+		return tree[si]; 
+	int mid = (ss + se)/2; 
+	return getSumUtil(ss, mid, qs, qe, 2*si+1) + 
+		getSumUtil(mid+1, se, qs, qe, 2*si+2); 
+}  
+int getSum(int n, int qs, int qe) 
+{ 
+	// Check for erroneous input values 
+	if (qs < 0 || qe > n-1 || qs > qe) 
+	{ 
+		printf("Invalid Input"); 
+		return -1; 
+	} 
+
+	return getSumUtil(0, n-1, qs, qe, 0); 
+} 
+
+// A recursive function that constructs Segment Tree for 
+// array[ss..se]. si is index of current node in segment 
+// tree st. 
+void constructSTUtil(int arr[], int ss, int se, int si) 
+{ 
+	// out of range as ss can never be greater than se 
+	if (ss > se) 
+		return ; 
+
+	// If there is one element in array, store it in 
+	// current node of segment tree and return 
+	if (ss == se) 
+	{ 
+		tree[si] = arr[ss]; 
+		return; 
+	} 
+
+	// If there are more than one elements, then recur 
+	// for left and right subtrees and store the sum 
+	// of values in this node 
+	int mid = (ss + se)/2; 
+	constructSTUtil(arr, ss, mid, si*2+1); 
+	constructSTUtil(arr, mid+1, se, si*2+2); 
+
+	tree[si] = tree[si*2 + 1] + tree[si*2 + 2]; 
+} 
+
+/* Function to construct segment tree from given array. 
+This function allocates memory for segment tree and 
+calls constructSTUtil() to fill the allocated memory */
+void constructST(int arr[], int n) 
+{ 
+	constructSTUtil(arr, 0, n-1, 0); 
+}  
+int main() 
+{ 	
+	int n;
+	cin>>n;
+	int arr[n];
+	for(int i=0;i<n;i++)cin>>arr[i];
+	constructST(arr, n); 
+	cout<<"\nEnter the range for which sum is to be computed ";
+	int l,h;
+	cin>>l>>h;
+	printf("Sum of values in given range = %d\n", 
+		getSum(n, l, h));
+	int val;	 
+	cout<<"\nEnter the range for which value is to be updated and also enter the value to be added ";
+	cin>>l>>h>>val;	
+	updateRange(n, l, h, val); 
+	printf("Updated sum of values in given range = %d\n", 
+			getSum( n, l, h)); 
+
+	return 0; 
+} 
+

data_structures/trie/C++/trie_impl.cpp

@@ -0,0 +1,56 @@
+#include<bits/stdc++.h>
+#define ll long long
+#define mp make_pair
+#define pb push_back
+using namespace std;
+const int alp_s = 26;
+struct Trie{
+	struct Trie *children[alp_s];
+	bool eow;
+};
+struct Trie *getnode(){
+	struct Trie *pnode = new Trie;
+	for(int i=0;i<26;i++){
+		pnode->children[i]=NULL;
+	}
+	pnode->eow=false;
+	return pnode;
+}
+void insert(struct Trie *root, string key){
+	struct Trie *ppoin = root;
+	int i,index;
+	for(i=0;i<key.length();i++){
+		index = key[i] - 'a';
+		if(!ppoin->children[index]){
+			ppoin->children[index] = getnode();
+		}
+		ppoin = ppoin->children[index];
+	}
+
+	ppoin->eow = true;
+}
+bool search(struct Trie *root, string key){
+	struct Trie *ppoin = root;
+	for(int i=0;i<key.length();i++){
+		int index = key[i] - 'a';
+		if(!ppoin->children[index])return false;
+		ppoin = ppoin->children[index];
+	}
+	return(ppoin!=NULL && ppoin->eow);
+}
+int main(){
+	int n;
+	cin>>n;
+	string keys[n];
+	for(int i=0;i<n;i++){
+		cin>>keys[i];
+	}
+	struct Trie *root = getnode();
+	for(int i=0;i<n;i++){
+		insert(root,keys[i]);
+	}
+	bool res = search(root,"pprt");
+	if(res)cout<<"Yes";
+	else cout<<"No";
+	return 0;
+}