Problem:
Range Update Query (RUQ)

Write a program which manipulates a sequence A = {a0, a1, . . . , an−1} with the following operations:

update(s, t, x): change as, as+1, ..., at to x.

find(i): output the value of ai.

Note that the initial values of ai (i = 0, 1, . . . , n−1) are 231-1.

Input

n q
query1
query2
:
queryq

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, ith query queryi is given in the following format:

0 s t x

or

1 i

The first digit represents the type of the query. '0' denotes update(s, t, x) and '1' denotes find(i).

Output

For each find operation, print the value.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

0 ≤ s ≤ t < n

0 ≤ i < n

0 ≤ x < 231−1

Sample Input 1

3 5
0 0 1 1
0 1 2 3
0 2 2 2
1 0
1 1

Sample Output 1

1
3

Sample Input 2

1 3
1 0
0 0 0 5
1 0

Sample Output 2

2147483647
5

Solution in C++ (judge verdict: Accepted)

#include<iostream>
#include<algorithm>
#include <stdio.h>
using namespace std;
typedef pair<int,int> p;
#define TREE_N (1<<17)

int c,n;
p tree[ TREE_N * 2 -1],ans;

void update(int i,int x,int t){
  i+=TREE_N-1;
  if(t==-1)tree[i]=p(-1,x);
  else ans=tree[i];
  while(i>0){
    i=(i-1)/2;
    if(t==-1)tree[i]=p(t,x);
    else ans=max(ans,tree[i]);
  }
}

void rec(int t,int a,int b,int k=0,int l=0,int r=TREE_N){
  if((l<a&&a<r)||(l<b&&b<r)){
    int m=(l+r)/2;
    rec(t,a,b,k*2+1,l,m);
    rec(t,a,b,k*2+2,m,r);
  }else if(a<=l&&r<=b){
    tree[k]=p(t,c);
  }
}

/*int Rec(int a,int b,int k=0,int l=0,int r=TREE_N){
  if((l<a&&a<r)||(l<b&&b<r)){
    int m=(l+r)/2;
    int left = Rec(a,b,k*2+1,l,m);
    int right = Rec(a,b,k*2+2,m,r);
    return min(left,right);
    
  }else if(a<=l&&r<=b){
    return tree[k];
  }else{
    return 2147483647;
  }
  }*/

int main(){
  int q,com,a,b;
  cin>>n>>q;
  for(int i=0;i<n;i++)update(i,2147483647,-1);
  for(int i=0;i<q;i++){
    cin>>com;
    if(com){
      cin>>a;
      update(a,0,0);
      cout<<ans.second<<endl;
    }
    else {
      cin>>a>>b>>c;
      rec(i,a,b+1);
    }
  }
  return 0;
}