Add files via upload

C++/MEX.cpp

@@ -0,0 +1,62 @@
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define MAXN 100001
+
+void constructMEX(int arr[], int N)
+{
+
+    int hash[MAXN] = { 0 };
+
+
+    for (int i = 0; i < N; i++) {
+
+        hash[arr[i]] = 1;
+    }
+
+
+    int MexOfArr;
+
+    // Find MEX of arr[]
+    for (int i = 1; i < MAXN; i++) {
+        if (hash[i] == 0) {
+            MexOfArr = i;
+            break;
+        }
+    }
+
+    // Stores MEX for all indices
+    int B[N];
+
+    // Traverse the given array
+    for (int i = 0; i < N; i++) {
+
+        // Update MEX
+        if (arr[i] < MexOfArr)
+            B[i] = arr[i];
+
+        // MEX default
+        else
+            B[i] = MexOfArr;
+    }
+
+    // Print the array B
+    for (int i = 0; i < N; i++)
+        cout << B[i] << ' ';
+}
+
+// Driver Code
+int main()
+{
+    // Given array
+    int arr[] = { 2, 1, 5, 3 };
+
+    // Given size
+    int N = sizeof(arr)
+            / sizeof(arr[0]);
+
+    // Function call
+    constructMEX(arr, N);
+    return 0;
+}

C++/hauff.cpp

@@ -0,0 +1,102 @@
+
+
+#include <bits/stdc++.h>
+using namespace std;
+
+// A Huffman tree node
+struct MinHeapNode {
+
+    // One of the input characters
+    char data;
+
+    // Frequency of the character
+    unsigned freq;
+
+    // Left and right child
+    MinHeapNode *left, *right;
+
+    MinHeapNode(char data, unsigned freq)
+
+    {
+
+        left = right = NULL;
+        this->data = data;
+        this->freq = freq;
+    }
+};
+
+// For comparison of
+// two heap nodes (needed in min heap)
+struct compare {
+
+    bool operator()(MinHeapNode* l, MinHeapNode* r)
+
+    {
+        return (l->freq > r->freq);
+    }
+};
+
+// Prints huffman codes from
+// the root of Huffman Tree.
+void printCodes(struct MinHeapNode* root, string str)
+{
+
+    if (!root)
+        return;
+
+    if (root->data != '$')
+        cout << root->data << ": " << str << "\n";
+
+    printCodes(root->left, str + "0");
+    printCodes(root->right, str + "1");
+}
+
+// The main function that builds a Huffman Tree and
+// print codes by traversing the built Huffman Tree
+void HuffmanCodes(char data[], int freq[], int size)
+{
+    struct MinHeapNode *left, *right, *top;
+
+    // Create a min heap & inserts all characters of data[]
+    priority_queue<MinHeapNode*, vector<MinHeapNode*>, compare> minHeap;
+
+    for (int i = 0; i < size; ++i)
+        minHeap.push(new MinHeapNode(data[i], freq[i]));
+
+    // Iterate while size of heap doesn't become 1
+    while (minHeap.size() != 1) {
+
+        // Extract the two minimum
+        // freq items from min heap
+        left = minHeap.top();
+        minHeap.pop();
+
+        right = minHeap.top();
+        minHeap.pop();
+
+        top = new MinHeapNode('$', left->freq + right->freq);
+
+        top->left = left;
+        top->right = right;
+
+        minHeap.push(top);
+    }
+
+    // Print Huffman codes using
+    // the Huffman tree built above
+    printCodes(minHeap.top(), "");
+}
+
+// Driver Code
+int main()
+{
+
+    char arr[] = { 'a', 'b', 'c', 'd', 'e', 'f' };
+    int freq[] = { 5, 9, 12, 13, 16, 45 };
+
+    int size = sizeof(arr) / sizeof(arr[0]);
+
+    HuffmanCodes(arr, freq, size);
+
+    return 0;
+}