Bzoj 1597: [Usaco2008 Mar] Land purchase 2011-12-27

1597: [Usaco2008 Mar] Land purchase

Time Limit:10 Sec Memory limit:162 MB
submit:697 solved:244
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Description farmer John prepares to expand his farm, and he is considering N (1 <= n <= 50,000) blocks of rectangular land. The length and width of each land is satisfied (1 <= wide <= 1,000,000; 1 <= long <= 1,000,000). The price of each piece of land is its area, but FJ can buy much faster land at the same time. The price of these lands is their largest length multiplied by their maximum width, but the length of the land cannot be exchanged. If FJ buys a 3x5 land and a 5x3, he needs to pay 5x5=25. FJ wanted to buy all the land, but he found that grouping to buy the land would save money. He needs you to help him find the minimum funds. input* line 1th: one number: N * 2nd. N+1 Line: Line i+1 contains two numbers, respectively, the length and width of block I land output* the first line: the minimum feasible cost. Sample Input4
100 1
15 15
20 5
1 100

Input explanation:

There are 4 pieces of land.

Sample Output
500

HINT

FJ 3 groups to buy these lands: The first group: 100x1, the second group of 1x100, the third group of 20x5 and 15x15 plot. Each group
The price is 100,100,300, a total of 500.

Source

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1 Program Stone;2 varI,j,n,bist,head,tail,insn:longint;3Len,wid,f,que:Array[0..100000] ofInt64;4 Procedure KP (t,w:longint);5  varI,j:longint;6 K,ml,mw:int64;7   begin8i:=t;j:=w;ml:=len[(T+W)Div 2];mw:=wid[(T+W)Div 2];9    RepeatTen      while(LEN[I]&GT;ML)or((LEN[I]=ML) and(WID[I]&LT;MW)) DoInc (i); One      while(LEN[J]&LT;ML)or((LEN[J]=ML) and(WID[J]&GT;MW)) DoDec (j); A     ifI<=j Then begin -k:=len[i];len[i]:=len[j];len[j]:=K; -k:=wid[i];wid[i]:=wid[j];wid[j]:=K; the Inc (I);d EC (j); -                  End; -    untilI>J; -    ifI<w ThenKP (i,w); +    ifJ>t ThenKP (t,j); -   End; +  functionDelhead (I,j,k:longint): boolean; A   begin at     iff[j]-f[k]>-wid[i]* (len[j+1]-len[k+1]) ThenExit (True)Elseexit (false); -   End; -  functionDeltail (I,j,k:longint): boolean; -   begin -     if(F[i]-f[j]) * (len[j+1]-len[k+1]) > (f[j]-f[k]) * (len[i+1]-len[j+1]) Thenexit (True) -                                                                        Elseexit (false); in   End; -  to Begin +Assign (Input,'input.in'); reset (input); - READLN (n); the    fori:=1  toN Do * readln (Len[i],wid[i]); $Kp1, n);Panax Notoginsenginsn:=0; bist:=0; -    fori:=1  toN Do the    begin +     ifWid[i]>bist Then begin Abist:=Wid[i]; the Inc (INSN); +len[insn]:=Len[i]; -wid[insn]:=Wid[i]; $                         End; $    End; -n:=INSN; -head:=0; tail:=0; the    fori:=1  toN Do -    beginWuyi       while(Tail>head) and(Delhead (i,que[head],que[head+1])) DoInc (head); thej:=Que[head]; -f[i]:=f[j]+wid[i]*len[j+1]; Wu       while(Tail>head) and(Deltail (i,que[tail],que[tail-1])) DoDec (tail); - Inc (tail); Aboutque[tail]:=i; $    End; - Writeln (F[n]); - close (input); - End. A  +  

Bzoj 1597: [Usaco2008 Mar] Land purchase 2011-12-27