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 Haskell (judge verdict: Time Limit Exceeded)

{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE UnboxedTuples #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE MultiWayIf #-}

import Control.Monad
import Control.Monad.ST
import Control.Monad.State
import Control.Applicative
import Control.Arrow
import Control.Monad.Primitive
import Data.List
import Data.Array
import Data.Array.IO
import Data.Maybe
import Data.Bits
import Data.Ord
import Data.Ratio
import Data.Int
import Data.Char
import qualified Data.ByteString.Char8 as BS
import qualified Data.Set as Set
import qualified Data.Vector as V
import qualified Data.Vector.Mutable as VM
import qualified Data.Vector.Unboxed as VU
import qualified Data.Vector.Unboxed.Mutable as VUM
import qualified Data.Vector.Generic as VG
import qualified Data.Vector.Generic.Mutable as VGM
import Data.Tuple
import Data.Function
import Text.Printf
import Debug.Trace
import Numeric

modifyArray arr i f = readArray arr i >>= \x -> writeArray arr i (f x)

listToTuple2 [a,b] = (a,b)
listToTuple3 [a,b,c] = (a,b,c)
listToTuple4 [a,b,c,d] = (a,b,c,d)
listToTuple5 [a,b,c,d,e] = (a,b,c,d,e)

readIntBS = fst . fromJust . BS.readInt

for = flip map

infixr 1 ?
(?) :: Bool -> (a,a) -> a
(?) b t = (if b then fst else snd) t

main :: IO ()
main = do
  [n,q] <- map read . words <$> getLine :: IO [Int]
  queries <- replicateM q $ map read . words <$> getLine :: IO [[Int]]
  let
    inf = 2^31-1
    f x y = if x == inf then y else x

  
  seg <- newLazySegmentTree n inf f :: IO (IOULazySegmentTree Int)

  forM_ queries $ \query -> do
    case query of
      [0,s,t,x] -> modifyLazySegmentTree seg s (t+1) (const x)
      [1,i] -> print =<< findLazySegmentTree seg i

    --mapM_ print =<< showLazySegmentTree seg 4
    --print ""
  
  

{-- 範囲更新・点取得のセグメント木--}
type MLazySegmentTree v s a = (v s a, a, (a -> a -> a)) -- (セグメント木, 単位元, 二項演算)
type STLazySegmentTree s a = MLazySegmentTree VM.MVector s a
type IOLazySegmentTree a = STLazySegmentTree RealWorld a
type STULazySegmentTree s a = MLazySegmentTree VUM.MVector s a
type IOULazySegmentTree a = STULazySegmentTree RealWorld a

newLazySegmentTree :: (PrimMonad m, VGM.MVector v a) => Int -> a -> (a -> a -> a) -> m (MLazySegmentTree v (PrimState m) a)
newLazySegmentTree n e f = return . (,e,f) =<< VGM.replicate m e
  where m = 2 * (2 ^ (ceiling $ logBase 2 (fromIntegral n))) - 1

modifyLazySegmentTree :: (PrimMonad m, VGM.MVector v a) => MLazySegmentTree v (PrimState m) a -> Int -> Int -> (a -> a) -> m ()
modifyLazySegmentTree (tree,e,f) x y g = do
  aux 0 0 n
  where
    n = (VGM.length tree) `div` 2 + 1
    aux i l r
      | r <= x || y <= l = return ()
      | x <= l && r <= y = VGM.read tree i >>= \a -> VGM.write tree i (g a)
      | otherwise = propag i >> aux (i*2+1) l ((l+r)`div`2) >> aux (i*2+2) ((l+r)`div`2) r
    propag i = do
      a <- VGM.read tree i
      when (i<n-1) $ do
        VGM.read tree (i*2+1) >>= \b -> VGM.write tree (i*2+1) (f a b)
        VGM.read tree (i*2+2) >>= \b -> VGM.write tree (i*2+2) (f a b)
        VGM.write tree i e

findLazySegmentTree :: (PrimMonad m, VGM.MVector v a) => MLazySegmentTree v (PrimState m) a -> Int -> m a
findLazySegmentTree (tree,e,f) i = do
  aux ((j-1)`div`2)
  VGM.read tree j
  where
    n = (VGM.length tree + 1) `div` 2
    j = i + n - 1
    aux x = do
      when (x >= 0) $ do
        aux ((x-1)`div`2)
        propag x

    propag i = do
      a <- VGM.read tree i
      when (i < n-1) $ do
        VGM.read tree (i*2+1) >>= \b -> VGM.write tree (i*2+1) (f a b)
        VGM.read tree (i*2+2) >>= \b -> VGM.write tree (i*2+2) (f a b)
        VGM.write tree i e

showLazySegmentTree :: (PrimMonad m, VGM.MVector v a, Show a) => MLazySegmentTree v (PrimState m) a -> Int -> m [String]
showLazySegmentTree (tree,_,_) len = do
  let
    n = (VGM.length tree) `div` 2 + 1
    xs = init $ scanl (+) 0 (takeWhile (<=n) (iterate (*2) 1))
    ys = reverse xs

  forM (zip xs ys) $ \(s,s') -> do
    return . concat =<< (forM [s..s*2] $ \i -> return . (\str -> "[" ++ (take' (len * (n `div` (s+1)) + s'*2) str) ++ "]") . show =<< VGM.read tree i)

  where
    take' n xs = if length t <= n then t ++ (replicate (n - length t) ' ') else t
      where t = take n xs