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31-oct-night

daa_1.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int fib_rec(int n){
+    if(n<=1) return n;
+    return fib_rec(n-1) + fib_rec(n-2);
+}
+
+int fib_iter(int n){
+    if(n<=1) return n;
+    int a = 0;
+    int b = 1;
+    int c;
+    for(int i=2;i<=n;i++){
+        c = a + b;
+        a = b;
+        b = c;
+    }
+    return c; 
+}
+
+int main(){
+
+    cout<<fib_rec(5)<<' '<<fib_iter(5)<<'\n';
+
+    return 0;
+}

daa_2.py

@@ -0,0 +1,46 @@
+import heapq
+
+# python abs_path.py cmd
+
+class Node:
+    def __init__(self, val, symbol) -> None:
+        self.val = val
+        self.symbol = symbol
+        self.huffman = ''
+        self.l = None
+        self.r = None
+
+    def __lt__(self, next):
+        return self.val < next.val
+
+nodes = []
+char = ['a', 'b', 'c', 'd', 'e']
+freq = [100, 12, 24, 105, 38]
+
+for i in range(len(char)):
+    heapq.heappush(nodes, Node(freq[i], char[i]))
+
+while len(nodes) > 1:
+    left = heapq.heappop(nodes)
+    right = heapq.heappop(nodes)
+    left.huffman = '0'
+    right.huffman = '1'
+
+    newNode = Node(left.val + right.val, left.symbol + right.symbol)
+    newNode.l = left
+    newNode.r = right
+    heapq.heappush(nodes, newNode)
+
+def printNodes(node, val=''):
+    newVal = val + node.huffman
+
+    if node.l:
+        printNodes(node.l, newVal)
+
+    if node.r:
+        printNodes(node.r, newVal)
+
+    if not node.l and not node.r:
+        print(f"{node.symbol} -> {newVal}")
+
+printNodes(nodes[0])

daa_3.cpp

@@ -0,0 +1,26 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+// 0/1 knapsack
+
+int knapsack(int i,int n,vector<int> &weights,vector<int> &values,int capacity,vector<vector<int>> &dp){
+    if(i == n || capacity == 0) return 0;
+    if(dp[i][capacity] != -1) return dp[i][capacity];
+    // if we could take we take
+    int ans1 = INT_MIN;
+    if(weights[i] <= capacity) ans1 = values[i] + knapsack(i+1,n,weights,values,capacity-weights[i],dp);
+    int ans2 = knapsack(i+1,n,weights,values,capacity,dp);
+    return dp[i][capacity] = max(ans1,ans2);
+}
+
+int main(){
+    vector<int> weights = {95, 4, 60, 32, 23, 72, 80, 62, 65, 46};
+    vector<int> values = {55, 10, 47, 5, 4, 50, 8, 61, 85, 87};
+    int n = 10;
+    int capacity = 269;
+
+    vector<vector<int>> dp(n+1,vector<int>(capacity+1,-1));
+    cout<<knapsack(0,n,weights,values,capacity,dp)<<'\n';
+
+    return 0;
+}

daa_4.cpp

@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+void print(vector<vector<char>> &a){
+    int n = a.size();
+    for(int i=0;i<n;i++){
+        for(int j=0;j<n;j++) cout<<a[i][j]<<' ';
+        cout<<'\n';
+    }
+    cout<<'\n';
+}
+
+bool isSafe(vector<vector<char>> &a,int i,int j){
+    int n = a.size();
+    for(int c=i-1;c>=0;c--) if(a[c][j] == 'Q') return false;
+    for(int x=i,y=j;x>=0 && y>=0;x--,y--) if(a[x][y] == 'Q') return false;
+    for(int x=i,y=j;x>=0 && y<n;x--,y++) if(a[x][y] == 'Q') return false;
+    return true;
+}
+
+void fun(int i,int n,vector<vector<char>> &a){
+    if(i >= n){
+        print(a);
+        return;
+    }
+    for(int j=0;j<n;j++){
+        if(isSafe(a,i,j)){
+            a[i][j] = 'Q';
+            fun(i+1,n,a);
+            a[i][j] = '-';
+        }
+    }
+}
+
+void solve(int n){
+    vector<vector<char>> a(n,vector<char>(n,'-'));
+    fun(0,n,a);
+}
+
+int main(){
+    int n = 5;
+    solve(n);
+
+    return 0;
+}