Merge pull request matthewsamuel95#795 from Nirav116/master

Create Matrix_Mutiplication.cpp

Author: matthewsamuel95

DP/MatrixChain_multiplication/Matrix_Mutiplication.cpp

@@ -0,0 +1,66 @@
+#include <bits/stdc++.h>
+using namespace std;
+int n=0;
+int val[100000];
+int m=1000000;
+int mx[1000][1000];
+void print(int x,int y)
+{
+	if(x==y)
+	{
+		cout<<x-1;
+	}
+	else
+	{
+		cout<<"(";
+		print(x,mx[y][x]);
+		print(mx[y][x]+1,y);
+		cout<<")";
+
+	}
+
+}
+
+void fun()
+{
+    
+    for(int i=0;i<=n;i++)
+        mx[i][i]=0;
+    for(int x=2;x<n;x++)
+    {
+        for(int j=1;j<n-x+1;j++)
+        {
+            int i=j+x-1;
+            mx[j][i]=m;
+            for(int k=j;k<i;k++)
+            {
+                
+                int w=mx[j][k]+mx[k+1][i]+val[j-1]*val[k]*val[i];
+		if(w<mx[j][i])
+		{
+		mx[i][j]=k;
+                mx[j][i]=min(mx[j][i],w);
+		}
+            }
+           
+            
+            
+        }
+    }
+	print(1,n-1);
+	cout<<endl;	
+    cout<<mx[1][n-1]<<endl;
+
+}
+
+int main() {
+  
+    cin>>n;
+    
+    for(int i=0;i<n;i++)
+    {
+        cin>>val[i];
+    }
+    fun();
+    return 0;
+}

Graph/FenwickTree/FenwickTree.cpp

@@ -0,0 +1,66 @@
+#include<bits/stdc++.h>
+
+using namespace  std;
+#define mx 100009
+typedef long long int ll;
+int arr[mx];
+int bit[mx];
+int n,m;
+void update(int index,ll  val)
+{
+    index+=1;
+    while(index<=n)
+    {
+        bit[index]+=val;
+        index += index & (-index);
+
+    }
+
+}
+ll getsum(int index)
+{
+    ll sum=0;
+    index+=1;
+    while(index>0)
+    {
+        //cout<<index<<" "<<bit[index]<<endl;
+        sum+=bit[index];
+        index-=index&(-index);
+    }
+    return sum;
+}
+int main()
+{
+
+    cin>>n>>m;
+    for(int i=0;i<n;i++)
+        cin>>arr[i];
+
+    memset(bit,0,sizeof bit);
+    for(int i=0;i<n;i++)
+    {
+        update(i,arr[i]);
+    }
+    int x,y,t;
+
+
+    while(m--)
+    {
+
+        cin>>t;
+        if(t==1)
+        {
+            cin>>x>>y;
+            ll diff=y-arr[x];
+            update(x,diff);
+            arr[x]=y;
+        }
+        else
+        {
+            cin>>x;
+
+            cout<<getsum(x)<<endl;
+        }
+    }
+    return 0;
+}