"BZOJ1560" "JSOI2009" Mars treasure Map [DP]

Mars treasure Map Time limit:10 Sec Memory limit:64 MB
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Input

　　

Output

　　

Sample Input4 10
1 1 20
10 10 10
3 5 60
5 3 30
Sample Output-4HINT

1<= M <=2000, 2<= N <=100000.

Main Idea

There is a benefit at each point, and the cost of going from one point to another is the square of Euclid's distance, asking for the maximum benefit from (M,M).

Solution

First, use DP. And if a < C < B, there is obviously (A-B) ^2 > (a-c) ^2 + (c-b) ^2.

Then we sort the horizontal axis, can guarantee the transverse size relationship . Then for a shift, each portrait is only as useful as the point closest to it. This makes it possible to do O (nm) .

Code

1#include <iostream>2#include <string>3#include <algorithm>4#include <cstdio>5#include <cstring>6#include <cstdlib>7#include <cmath>8 using namespacestd; 9typedefLong LongS64;Ten   One Const intone =500005; A Const intINF =2147483640; -   - intn,m; the intPos[one]; - intF[one]; -   - structPower + { -         intx, y, z + }a[one]; A   at BOOLcmpConstPower &a,ConstPower &b) - { -         if(a.x! = b.x)returnA.x <b.x; -         returnA.y <b.y; - } -   in intCostintAxintAy,intBxintby ) - { to         return(AX-BX) * (AX-BX) + (ay-by) * (Ay-by ); + } -   the int Get() * {     $         intres=1, q=1;CharC; Panax Notoginseng          while((C=getchar ()) < -|| C> $ )  -         if(c=='-') q=-1;  theres=c- -;  +          while((C=getchar ()) >= -&& c<= $ )     ARes=res*Ten+c- -;  the         returnRes*Q; + } -   $ intMain () $ { -n =Get(); m =Get(); -          for(intI=1; i<=n; i++) thea[i].x =Get(), a[i].y =Get(), a[i].z =Get(); -Sort (A +1, a+n+1, CMP);Wuyi           theMemset (F,-127,sizeof(f)); -pos[1] =1; f[1] =0; Wu          for(intId=1; id<=n; id++) -         { About             intx = a[id].x, y =a[id].y; $             intRecord =-INF; -              for(intj=1; j<=y; J + +) -             if(Pos[j]) -Record = max (record, F[j]-Cost (pos[j],j, x, y)); A                   +Pos[y] =x; theF[y] = record +a[id].z; -         } $           theprintf"%d", F[m]); the } the 

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"BZOJ1560" "JSOI2009" Mars treasure Map [DP]