POJ 3666 Making the Grade (DP+离散化)

#include <iostream>
#include <string.h>
#include <math.h>
#include <queue>
#include <algorithm>
#include <stdlib.h>
#include <map>
#include <set>
#include <stdio.h>
using namespace std;
#define LL long long
#define pi acos(-1.0)
const int mod=1e9+7;
const int INF=1E15;
const double eqs=1e-9;
const int MAXN=2000+10;
LL a[MAXN], dp[MAXN][MAXN], b[MAXN];
LL Abs(LL x)
{
return x>0?x:-x;
}
int main()
{
int n, i, j;
LL min1, ans1, ans2;
scanf("%d",&n);
for(i=1;i<=n;i++){
scanf("%lld",&a[i]);
b[i]=a[i];
}
sort(a+1,a+n+1);
memset(dp,0,sizeof(dp));
for(i=1;i<=n;i++){
min1=INF;
for(j=1;j<=n;j++){
min1=min(min1,dp[i-1][j]);
dp[i][j]=Abs(a[j]-b[i])+min1;
}
}
ans1=INF;
for(i=1;i<=n;i++){
ans1=min(ans1,dp
[i]);
}
memset(dp,0,sizeof(dp));
for(i=1;i<=n;i++){
min1=INF;
for(j=n;j>=1;j--){
min1=min(min1,dp[i-1][j]);
dp[i][j]=Abs(a[j]-b[i])+min1;
}
}
ans2=INF;
for(i=1;i<=n;i++){
ans2=min(ans2,dp
[i]);
}
printf("%lld\n",min(ans1,ans2));
return 0;
}