rmq

Author: sayedppqq

Data Structure/RMQ using Sparse Table.cpp

@@ -0,0 +1,107 @@
+#include<bits/stdc++.h>
+#include<ext/pb_ds/assoc_container.hpp>
+#include<ext/pb_ds/tree_policy.hpp>
+#define  FIO        ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
+#define  Fileio     freopen("output.txt","w",stdout);freopen("input.txt","r",stdin);
+#define  all(v)     v.begin(),v.end()
+#define  rall(v)    v.rbegin(),v.rend()
+#define  MEM(a,x)   memset(a,x,sizeof(a))
+#define  SZ(v)      v.size()
+#define  nl         "\n"
+#define  bug        cout<<"bug"<<nl;
+#define  pi         acos(-1.0)
+#define  ll     long long
+#define  pb     push_back
+#define  mp     make_pair
+#define  pii    pair< int,int >
+#define  pll    pair< ll,ll >
+#define  vii    vector< int >
+#define  vll    vector< ll >
+#define  vpi    vector< pii >
+#define  vpl    vector<pll>
+#define  MX     100005
+#define  EPS    1e-12
+#define  ss     second
+#define  ff     first
+using namespace std;
+using namespace __gnu_pbds;
+
+template<typename T>
+using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
+template<typename T>
+using ordered_multiset=tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;
+
+inline ll powr(int a,int b){ll res=1;while(b){if(b&1) res*=a;a*=a;b/=2;}return res;}
+int cases=1;
+
+#ifdef ppqq
+     #define debug(...) __f(#__VA_ARGS__, __VA_ARGS__)
+    template < typename Arg1 >
+    void __f(const char* name, Arg1&& arg1){
+        cerr << name << " is " << arg1 << std::endl;
+    }
+    template < typename Arg1, typename... Args>
+    void __f(const char* names, Arg1&& arg1, Args&&... args){
+        const char* comma = strchr(names+1, ',');
+        cerr.write(names, comma - names) << " is " << arg1 <<"  ";
+        __f(comma+1, args...);
+    }
+#else
+    #define debug(...)
+#endif
+
+///******************************************START******************************************
+
+///Problem Link : https://www.spoj.com/problems/RMQSQ/
+
+const int LOG=20;
+int maxPower[MX],ara[MX],sparse[MX][LOG];
+
+void makingSparseTable(int n)
+{
+    for(int i=0;i<n;i++) sparse[i][0]=ara[i];
+
+    for(int i=1;i<LOG;i++)
+    {
+        for(int j=0;j+(1<<i)-1<n;j++)
+        {
+            sparse[j][i]=min(sparse[j][i-1],sparse[j+(1<<(i-1))][i-1]);
+        }
+    }
+
+}
+void preprocess(int n)
+{
+    maxPower[1]=0;
+    for(int i=2;i<=n;i++) maxPower[i]=maxPower[i/2]+1;
+
+    makingSparseTable(n);
+}
+
+int RMQ(int L,int R)
+{
+    int len=R-L+1;
+    int maxLogValue=maxPower[len];
+
+    return min(sparse[L][maxLogValue] , sparse[R-(1<<maxLogValue)+1][maxLogValue]);
+}
+int main()
+{
+    FIO;
+
+    int n,q;
+    cin>>n;
+    for(int i=0;i<n;i++) cin>>ara[i];
+
+    preprocess(n);
+
+    cin>>q;
+
+    while(q--)
+    {
+        int L,R;
+        cin>>L>>R;
+
+        cout<<RMQ(L,R)<<nl;
+    }
+}