1113: [Poi2008] Poster pla

1113: [Poi2008] Poster pla time limit:10 Sec Memory limit:162 MB
submit:765 solved:466
[Submit] [Status] [Discuss] Description

n rectangles, lined up in a row. Now you want to cover them with as few rectangular posters as possible.

Input

The first line gives the number n, which means there are n rectangles. N under [1,250000] n rows, each row gives the length and width of the rectangle. Its value in [1,1000000000]2 postering

Output

The minimum number of posters.

Sample Input5
1 2
1 3
2 2
2 5
1 4

Sample Output4

HINT Source

The puzzle: A cute and monotonous stack, explained below (obviously, the width of what does not know the role of where = =, acknowledgements zyf-zyf god Ben, Wish rp++, abuse Farm + +)

Exercises

Ans is at most equal to N, so under what circumstances can ans be reduced?

First, if it is reduced, it must be a poster, covering two rectangles of the same height (width is soy sauce ...). ）

So if H[I]=H[J] then you have to make sure that I and J are no taller than they are.

Hey? Think of what, right, monotonous stack! Maintains a monotonically decreasing stack when the element = Stack top element is ans--, and the stack top element is bounced

1/**************************************************************2Problem:11133 User:hansbug4 language:pascal5 result:accepted6Time:3884Ms7Memory:8040KB8****************************************************************/9  Ten var One I,k,l,m,n:longint;j:int64; AA:Array[0..1000005] ofInt64; - begin -READLN (n); l:=n;k:=0; the       fori:=1  toN Do -          begin - readln (j,j); -                whileJ<=A[K] Do +                     begin -                          ifJ=A[K] ThenDec (l); + Dec (k); A                     End; atInc (k); a[k]:=J; -          End; - Writeln (l); - End.

1113: [Poi2008] Poster pla