【BZOJ1560】【JSOI2009】火星藏宝图 [DP]

Description

#include<iostream>
#include<string>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
using namespace std;
typedef long long s64;

const int ONE = 500005;
const int INF = 2147483640;

int n,m;
int pos[ONE];
int f[ONE];

struct power
{
int x,y,z;
}a[ONE];

bool cmp(const power &a, const power &b)
{
if(a.x != b.x) return a.x < b.x;
return a.y < b.y;
}

int cost(int Ax, int Ay, int Bx, int By)
{
return (Ax - Bx) * (Ax - Bx) + (Ay - By) * (Ay - By);
}

int get()
{
int res=1,Q=1;char c;
while( (c=getchar())<48 || c>57 )
if(c=='-')Q=-1;
res=c-48;
while( (c=getchar())>=48 && c<=57 )
res=res*10+c-48;
return res*Q;
}

int main()
{
n = get();   m = get();
for(int i=1; i<=n; i++)
a[i].x = get(),  a[i].y = get(), a[i].z = get();
sort(a+1, a+n+1, cmp);

memset(f, -127, sizeof(f));
pos[1] = 1; f[1] = 0;
for(int id=1; id<=n; id++)
{
int x = a[id].x, y = a[id].y;
int record = -INF;
for(int j=1; j<=y; j++)
if(pos[j])
record = max( record, f[j] - cost(pos[j],j, x,y) );

pos[y] = x;
f[y] = record + a[id].z;
}

printf("%d", f[m]);
}