Sorted Subsegments


Problem Statement :


Consider an array  of  integers. We perform  queries of the following type on :

Sort all the elements in the subsegment .
Given , can you find and print the value at index  (where ) after performing  queries?

Input Format

The first line contains three positive space-separated integers describing the respective values of  (the number of integers in ),  (the number of queries), and  (an index in ).
The next line contains  space-separated integers describing the respective values of .
Each line  of the  subsequent lines contain two space-separated integers describing the respective  and  values for query .

Output Format

Print a single integer denoting the value of  after processing all q  queries.



Solution :



title-img


                            Solution in C :

In  C  :





#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>


struct Query{
	int l, r;
	int ignore;
};

int ar1[75000];
int ar2[75000];

struct Query queries[75000];
struct Query sarea[75000];


int cmp(const void *a, const void *b){
	return (*(int *)a - *(int *)b);
}

void insertionsort(int a[], int N){
	int i, j;
	int v;
	for (i = 1; i < N; i++){
		v = a[i];
		for (j = i; j>0 && a[j - 1] > v; j--){
			a[j] = a[j - 1];
		}
		a[j] = v;
	}
}

int main() {

	int n, q, k1, i, l, r, ign, j,mi,hr,nr,k,changed;
    int si, sj;
	int *a = ar1;
	int *b = ar2;

	scanf("%d %d %d", &n, &q, &k1);
	for (i = 0; i<n; i++){
		scanf("%d", &a[i]);
	}
	for (i = 0; i<q; i++){
		scanf("%d %d", &(queries[i].l), &(queries[i].r));
		queries[i].ignore = 0;
	}
	i = q ;
	do{
		i = i - 1;		
	} while (i >= 0 && (k1 < queries[i].l || k1 > queries[i].r));
	if (i >= 0){
		l = queries[i].l;
		r = queries[i].r;
		ign = i;
		for (i = i-1; i >= 0; i--){
			if (queries[i].r < l || queries[i].l > r){
				queries[i].ignore = 1;
			}
			else{
				if (queries[i].r > r && queries[i].l >= l)
					r = queries[i].r;
				else if (queries[i].l < l && queries[i].r <= r)
					l = queries[i].l;
				else  if (queries[i].l < l && queries[i].r > r){
					ign = i;
					r = queries[i].r;
					l = queries[i].l;
				}
			}
		}
		l = 0;
		r = 0;
        si = 0;
		for (i = 0; i <= ign; i++){

			if (!queries[i].ignore){
                for (sj = si - 1; sj >= 0; sj--){
					if (sarea[sj].l < queries[i].l && queries[i].l < sarea[sj].r) break;
					if (sarea[sj].l < queries[i].r && queries[i].r < sarea[sj].r) break;
   					if (sarea[sj].l >= queries[i].l && queries[i].r >= sarea[sj].r) break;
				}
				if (sj == -1){
					qsort(a + queries[i].l, queries[i].r - queries[i].l + 1, sizeof(int), cmp);
					sarea[si] = queries[i];
					si++;
				}
				else{
                    changed =0;
                    l = sarea[sj].l;
					r = sarea[sj].r;
					if (queries[i].l < l){
                        changed=1;
						hr = l - queries[i].l;
						memcpy(b, a + queries[i].l, hr*sizeof(int));
						//qsort(b, hr, sizeof(int), cmp);
                        insertionsort(b,hr);
						mi = 0;
						j = l;
						k = queries[i].l;
						nr = (r < queries[i].r ? r : queries[i].r);
						while (mi < hr && j <= nr)
						{
							a[k++] = (b[mi] < a[j] ? b[mi++] : a[j++]);
						}
						while (mi < hr) a[k++] = b[mi++];
						
					}
					if (queries[i].r > r){
                        changed+=2;
						hr = queries[i].r - r;
						memcpy(b, a + r + 1, hr*sizeof(int));
						//qsort(b, hr, sizeof(int), cmp);
                        insertionsort(b,hr);
						mi = hr - 1;
						j = r;
						k = queries[i].r;

						while (mi >= 0 && j >= queries[i].l)
						{
							a[k--] = (b[mi] > a[j] ? b[mi--] : a[j--]);
						}
						while (mi >= 0) a[k--] = b[mi--];
						r = queries[i].r;
					}
                    if (changed){
						sarea[sj].l = queries[i].l;
						sarea[sj].r = queries[i].r;
					}
				}
			}
		}
	}
	printf("%d", a[k1]);
	return 0;
}
                        


                        Solution in C++ :

In  C++  :






#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }

typedef char Val;
struct Sum {
	int cnt;
	Sum() : cnt(0) {}
	Sum(const Val &val, int pos) : cnt(val) {}
	Sum &operator+=(const Sum &that) { cnt += that.cnt; return *this; }
	Sum operator+(const Sum &that) const { return Sum(*this) += that; }
};
struct Add {
	int assign;
	Add() : assign(-1) {}
	explicit Add(int a) : assign(a) {}
	Add &operator+=(const Add &that) {
		if(that.assign != -1)
			assign = that.assign;
		return *this;
	}
	void addToVal(Val &val, int pos) const {
		if(assign != -1)
			val = assign != 0;
	}
	void addToSum(Sum &sum, int left, int right) const {
		if(assign != -1)
			sum.cnt = assign != 0 ? right - left : 0;
	}
};

struct SegmentTree {
	vector<Val> leafs;
	vector<Sum> nodes;
	vector<Add> add;
	vector<int> leftpos, rightpos;
	int n, n2;
	void init(int n_, const Val &v = Val()) { init(vector<Val>(n_, v)); }
	void init(const vector<Val> &u) {
		n = 1; while(n < (int)u.size()) n *= 2;
		n2 = (n - 1) / 2 + 1;
		leafs = u; leafs.resize(n, Val());
		nodes.resize(n);
		for(int i = n - 1; i >= n2; -- i)
			nodes[i] = Sum(leafs[i * 2 - n], i * 2 - n) + Sum(leafs[i * 2 + 1 - n], i * 2 + 1 - n);
		for(int i = n2 - 1; i > 0; -- i)
			nodes[i] = nodes[i * 2] + nodes[i * 2 + 1];
		add.assign(n, Add());

		leftpos.resize(n); rightpos.resize(n);
		for(int i = n - 1; i >= n2; -- i) {
			leftpos[i] = i * 2 - n;
			rightpos[i] = (i * 2 + 1 - n) + 1;
		}
		for(int i = n2 - 1; i > 0; -- i) {
			leftpos[i] = leftpos[i * 2];
			rightpos[i] = rightpos[i * 2 + 1];
		}
	}
	Val get(int i) {
		int indices[128];
		int k = getIndices(indices, i, i + 1);
		propagateRange(indices, k);
		return leafs[i];
	}
	Sum getRangeCommutative(int i, int j) {
		int indices[128];
		int k = getIndices(indices, i, j);
		propagateRange(indices, k);
		Sum res = Sum();
		for(int l = i + n, r = j + n; l < r; l >>= 1, r >>= 1) {
			if(l & 1) res += sum(l ++);
			if(r & 1) res += sum(-- r);
		}
		return res;
	}
	Sum getRange(int i, int j) {
		int indices[128];
		int k = getIndices(indices, i, j);
		propagateRange(indices, k);
		Sum res = Sum();
		for(; i && i + (i&-i) <= j; i += i&-i)
			res += sum((n + i) / (i&-i));
		for(k = 0; i < j; j -= j&-j)
			indices[k ++] = (n + j) / (j&-j) - 1;
		while(-- k >= 0) res += sum(indices[k]);
		return res;
	}
	void set(int i, const Val &x) {
		int indices[128];
		int k = getIndices(indices, i, i + 1);
		propagateRange(indices, k);
		leafs[i] = x;
		mergeRange(indices, k);
	}
	void addToRange(int i, int j, const Add &x) {
		if(i >= j) return;
		int indices[128];
		int k = getIndices(indices, i, j);
		propagateRange(indices, k);
		int l = i + n, r = j + n;
		if(l & 1) { int p = (l ++) - n; x.addToVal(leafs[p], p); }
		if(r & 1) { int p = (-- r) - n; x.addToVal(leafs[p], p); }
		for(l >>= 1, r >>= 1; l < r; l >>= 1, r >>= 1) {
			if(l & 1) add[l ++] += x;
			if(r & 1) add[-- r] += x;
		}
		mergeRange(indices, k);
	}
private:
	int getIndices(int indices[], int i, int j) const {
		int k = 0, l, r;
		if(i >= j) return 0;
		for(l = (n + i) >> 1, r = (n + j - 1) >> 1; l != r; l >>= 1, r >>= 1) {
			indices[k ++] = l;
			indices[k ++] = r;
		}
		for(; l; l >>= 1) indices[k ++] = l;
		return k;
	}
	void propagateRange(int indices[], int k) {
		for(int i = k - 1; i >= 0; -- i)
			propagate(indices[i]);
	}
	void mergeRange(int indices[], int k) {
		for(int i = 0; i < k; ++ i)
			merge(indices[i]);
	}
	inline void propagate(int i) {
		if(i >= n) return;
		add[i].addToSum(nodes[i], leftpos[i], rightpos[i]);
		if(i * 2 < n) {
			add[i * 2] += add[i];
			add[i * 2 + 1] += add[i];
		} else {
			add[i].addToVal(leafs[i * 2 - n], i * 2 - n);
			add[i].addToVal(leafs[i * 2 + 1 - n], i * 2 + 1 - n);
		}
		add[i] = Add();
	}
	inline void merge(int i) {
		if(i >= n) return;
		nodes[i] = sum(i * 2) + sum(i * 2 + 1);
	}
	inline Sum sum(int i) {
		propagate(i);
		return i < n ? nodes[i] : Sum(leafs[i - n], i - n);
	}
};

int main() {
	int n; int q; int k;
	while(~scanf("%d%d%d", &n, &q, &k)) {
		vector<int> A(n);
		for(int i = 0; i < n; ++ i)
			scanf("%d", &A[i]);
		vector<int> l(q), r(q);
		for(int i = 0; i < q; ++ i)
			scanf("%d%d", &l[i], &r[i]), ++ r[i];
		vi values = A;
		sort(values.begin(), values.end());
		values.erase(unique(values.begin(), values.end()), values.end());
		int lo = 0, up = (int)values.size() - 1;
		while(up - lo > 0) {
			int mid = (lo + up + 1) / 2;
			vector<Val> initvals(n);
			rep(i, n)
				initvals[i] = values[mid] <= A[i];
			SegmentTree segt; segt.init(initvals);
			rep(i, q) {
				int cnt0 = r[i] - l[i] - segt.getRangeCommutative(l[i], r[i]).cnt;
				segt.addToRange(l[i], l[i] + cnt0, Add(0));
				segt.addToRange(l[i] + cnt0, r[i], Add(1));
			}
			if(segt.get(k))
				lo = mid;
			else
				up = mid - 1;
		}
		printf("%d\n", values[lo]);
	}
	return 0;
}
                    


                        Solution in Java :

In  Java :





import java.io.*;
import java.util.*;

public class Solution {
  private static InputReader in;
  private static PrintWriter out;
  
  public static int[] brr;
  
  static class SegmentTree {
    public SegmentTree left, right;
    public int nones, start, end;
    public int pushval;
    
    public SegmentTree(int start, int end) {
      this.start = start;
      this.end = end;
      this.pushval = -1;
      if (start != end) {
        int mid = (start + end) >> 1;
        left = new SegmentTree(start, mid);
        right = new SegmentTree(mid+1, end);
        nones = left.nones + right.nones;
      } else {
        nones = brr[start] == 1 ? 1 : 0;
      }
    }
    
    public int size() {
      return end-start+1;
    }
    
    public void push() {
      if (left == null) return;
      if (pushval == -1) return;
      left.nones = pushval == 1 ? left.size() : 0;
      left.pushval = pushval;
      right.nones = pushval == 1 ? right.size() : 0;
      right.pushval = pushval;
      pushval = -1;
    }
    public void join() {
      if (left == null) return;
      this.nones = left.nones+right.nones;
    }
    
    public int count(int s, int e) {
      if (start == s && end == e) return nones;
      push();
      int mid = (start + end) >> 1;
      if (mid >= e) return left.count(s, e);
      else if (mid < s) return right.count(s,e);
      else return left.count(s,mid)+right.count(mid+1,e);
    }
    
    public void set(int s, int e, int val) {
      if (s > e) return;
      if (start == s && end == e) {
        this.pushval = val;
        this.nones = val == 1 ? this.size() : 0;
        return;
      }
      push();
      int mid = (start+end) >> 1;
      if (mid >= e) {left.set(s, e, val);}
      else if (mid < s) {right.set(s,e,val);}
      else {
        left.set(s,mid,val);
        right.set(mid+1,e,val);
      }
      join();
    }
  }

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out, true);

    int n = in.nextInt(), q = in.nextInt(), k = in.nextInt();
    int[] arr = new int[n];
    for (int i = 0; i < n; i++) {
      arr[i] = in.nextInt();
    }
    HashSet<Integer> dis = new HashSet<>();
    for (int i = 0; i < n; i++) {
      dis.add(arr[i]);
    }
    ArrayList<Integer> ls = new ArrayList<>(dis);
    Collections.sort(ls);
    
    int[] l = new int[q];
    int[] r = new int[q];
    for (int i = 0; i < q; i++) {
      l[i] = in.nextInt();
      r[i] = in.nextInt();
    }
    
    int lo = 0, hi = ls.size()-1;
    while(lo<hi) {
      int mid = (lo+hi+1) >> 1;
      brr = new int[n];
      for (int i = 0; i < n; i++) {
        brr[i] = arr[i] < ls.get(mid) ? 0 : 1;
      }
      SegmentTree root = new SegmentTree(0, n-1);
      for (int i = 0; i < q; i++) {
        int a = root.count(l[i], r[i]);
        root.set(l[i], r[i], 0);
        root.set(r[i]-a+1, r[i], 1);
      }
      int x = root.count(k, k);
      if (x == 1) {
        lo = mid;
      } else {
        hi = mid-1;
      }
    }
    
    out.println(ls.get(lo));
    out.close();
    System.exit(0);
  }

  static class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
      reader = new BufferedReader(new InputStreamReader(stream), 32768);
      tokenizer = null;
    }

    public String next() {
      while (tokenizer == null || !tokenizer.hasMoreTokens()) {
        try {
          tokenizer = new StringTokenizer(reader.readLine());
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
      return tokenizer.nextToken();
    }

    public int nextInt() {
      return Integer.parseInt(next());
    }
  }


}
                    


                        Solution in Python : 
                            
In  Python3 :







import sys

##### Read Data
dat = [x.split() for x in sys.stdin.readlines()]
N = int(dat[0][0])
Q = int(dat[0][1])
k = int(dat[0][2])
a = list(map(int, dat[1]))
q = [list(map(int, x)) for x in dat[2:len(dat)]]

##### Process Queries
b = sorted(a)
lmin, rmax, pmax, qmin = (N-1), 0, 0, (N-1)    
pmin, qmax, flag = (N-1), 0, 1
count, span_q, ladder, revlad = [], 0, 0, 0
if Q >= 2:
    ladder = all(q[i+1][0] > q[i][0] for i in range(Q-1)) 
    revlad = all(q[i+1][1] < q[i][1] for i in range(Q-1))

if a != b and ladder < 1 and revlad < 1:
    for i in range(Q):
        l, r = q[i][0], q[i][1]       
        
        if (r-l) > (rmax-lmin):
            lmin, rmax = l, r	
        
        if l < pmin:
            pmin, pmax = l, r
        elif l == pmin and pmax < r:
            pmax = r
            
        if r > qmax:
            qmin, qmax = l, r
        elif r == qmax and qmin > l:
            qmin = l
    
    for i in range(Q):
        l, r = q[i][0], q[i][1]
        
        if l > lmin and r < rmax: continue     
        if l > pmin and r < pmax: continue             
        if l > qmin and r < qmax: continue        
        
        if i < (Q-1):
            if l >= q[i+1][0] and r <= q[i+1][1]:
                continue
            
        if i > 0:
            if l >= q[i-flag][0] and r <= q[i-flag][1]:
                flag += 1
                continue
            else:
                flag = 1

        count += [i]
        span_q += r-l+1

# Perform Queries 
if ladder > 0:
    l, r, Qu = q[0][0], q[0][1], int((k+5)/5)
    a[l:r+1] = sorted(a[l:r+1])
    for i in range(1, Q):
        l, r, r0, m, sig = q[i][0], q[i][1], q[i-1][1], 0, 0
        if l > r0 or (r-r0) > 0.1*(r0-l):
            a[l:r+1] = sorted(a[l:r+1])
            continue
        if k < l: break
        count = list(range(r0+1, r+1))
        for j in range(len(count)):
            p, new_A = count[j], a[count[j]]
            l, r0 = q[i][0], q[i-1][1]
            if a[l] >= new_A:
                del(a[p]); a[l:l] = [new_A]; continue
            elif a[r0+j-1] <= new_A:
                del(a[p]); a[r0+j:r0+j] = [new_A]; continue   
            while sig < 1:
                m = int((l+r0)/2)
                if a[m] > new_A:
                    r0 = m
                elif a[m+1] < new_A:
                    l = m+1
                else:
                    del(a[p]); a[m+1:m+1] = [new_A]                
                    sig = 1

elif revlad > 0:
    l, r, Qu = q[0][0], q[0][1], int((k+5)/5)
    a[l:r+1] = sorted(a[l:r+1])
    for i in range(1, Q):
        l, r, l0, m, sig = q[i][0], q[i][1], q[i-1][0], 0, 0
        if k > r: break
        if r < l0:
            a[l:r+1] = sorted(a[l:r+1]); continue        
        count = list(range(l, l0))
        for j in range(len(count)):
            p, new_A = count[j], a[count[j]]
            if a[l0] >= new_A:
                del(a[p]); a[l0:l0] = [new_A]; continue
            elif a[r] <= new_A:
                del(a[p]); a[r:r] = [new_A]; continue   
            while sig < 1:
                m = int((l0+r)/2)
                if a[m] > new_A:
                    r = m
                elif a[m+1] < new_A:
                    l0 = m+1
                else:
                    del(a[p]); a[m+1:m+1] = [new_A]                
                    sig = 1
    
elif span_q < 1e9 and a != b:
    for i in count:
        l, r = q[i][0], q[i][1]
        a[l:(r+1)] = sorted(a[l:(r+1)])
else:
    a[pmin:qmax+1] = sorted(a[pmin:qmax+1])   
print(a[k])
                    


View More Similar Problems

Kindergarten Adventures

Meera teaches a class of n students, and every day in her classroom is an adventure. Today is drawing day! The students are sitting around a round table, and they are numbered from 1 to n in the clockwise direction. This means that the students are numbered 1, 2, 3, . . . , n-1, n, and students 1 and n are sitting next to each other. After letting the students draw for a certain period of ti

View Solution →

Mr. X and His Shots

A cricket match is going to be held. The field is represented by a 1D plane. A cricketer, Mr. X has N favorite shots. Each shot has a particular range. The range of the ith shot is from Ai to Bi. That means his favorite shot can be anywhere in this range. Each player on the opposite team can field only in a particular range. Player i can field from Ci to Di. You are given the N favorite shots of M

View Solution →

Jim and the Skyscrapers

Jim has invented a new flying object called HZ42. HZ42 is like a broom and can only fly horizontally, independent of the environment. One day, Jim started his flight from Dubai's highest skyscraper, traveled some distance and landed on another skyscraper of same height! So much fun! But unfortunately, new skyscrapers have been built recently. Let us describe the problem in one dimensional space

View Solution →

Palindromic Subsets

Consider a lowercase English alphabetic letter character denoted by c. A shift operation on some c turns it into the next letter in the alphabet. For example, and ,shift(a) = b , shift(e) = f, shift(z) = a . Given a zero-indexed string, s, of n lowercase letters, perform q queries on s where each query takes one of the following two forms: 1 i j t: All letters in the inclusive range from i t

View Solution →

Counting On a Tree

Taylor loves trees, and this new challenge has him stumped! Consider a tree, t, consisting of n nodes. Each node is numbered from 1 to n, and each node i has an integer, ci, attached to it. A query on tree t takes the form w x y z. To process a query, you must print the count of ordered pairs of integers ( i , j ) such that the following four conditions are all satisfied: the path from n

View Solution →

Polynomial Division

Consider a sequence, c0, c1, . . . , cn-1 , and a polynomial of degree 1 defined as Q(x ) = a * x + b. You must perform q queries on the sequence, where each query is one of the following two types: 1 i x: Replace ci with x. 2 l r: Consider the polynomial and determine whether is divisible by over the field , where . In other words, check if there exists a polynomial with integer coefficie

View Solution →