bzoj 1560 [JSOI2009]火星藏宝图（DP）

1560: [JSOI2009]火星藏宝图

Time Limit: 10 Sec  Memory Limit: 64 MB
Submit: 647  Solved: 309
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Description

Input

Output

Sample Input

4 10
1 1 20
10 10 10
3 5 60
5 3 30

Sample Output

-4

HINT

Source

JSOI2009Day2

【代码】

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 using namespace std;

 typedef long long LL;
 const int maxn = +;
 const int maxm = +;
 const int INF = 1e9;

 struct node{
     int x,y,p;
     bool operator<(const node& rhs) const{
         return (x<rhs.x)||(x==rhs.x && y<rhs.y);
     }
 }a[maxm];

 int pos[maxn],n,m;
 LL d[maxn];

 int read(int& x) {
     char c=getchar();
     while(!isdigit(c)) c=getchar();
     x=;
     while(isdigit(c)) x=x*+c-'',c=getchar();
 }

 int main() {
     scanf("%d%d",&n,&m);
     n+=;
     a[].x=a[].y=;
     a[].x=a[].y=m;
     for(int i=;i<=n;i++)
         read(a[i].x),read(a[i].y),read(a[i].p);
     sort(a+,a+n+);
     pos[]=;
     for(int i=;i<=n;i++) {
         LL tmp=-INF;
         for(int j=;j<=a[i].y;j++) if(pos[j])
             tmp=max(tmp,d[j]-(a[i].y-j)*(a[i].y-j)-(a[i].x-pos[j])*(a[i].x-pos[j]));
         pos[a[i].y]=a[i].x , d[a[i].y]=tmp+a[i].p;
     }
     printf("%lld\n",d[m]);
     return ;
 }