BZOJ1742[Usaco2005 nov]Grazing on the Run 边跑边吃草
费用提前计算的DP..
1 #include <iostream> 2 #include <algorithm> 3 #include <cstdio> 4 #include <cstring> 5 using namespace std; 6 #define INF 0x3f3f3f3f 7 #define MAXN 1005 8 int dp[2][MAXN][MAXN]; 9 int x[MAXN]; 10 int n,x0; 11 int main() 12 { 13 scanf("%d%d",&n,&x0); 14 for(int i=1;i<=n;i++) 15 scanf("%d",&x[i]); 16 x[++n]=x0; 17 sort(x+1,x+n+1); 18 for(int i=1;i<=n;i++) 19 if(x[i]!=x0)dp[0][i][i]=dp[1][i][i]=INF; 20 else 21 dp[0][i][i]=dp[1][i][i]=0; 22 for(int i=n;i>=1;i--) 23 for(int j=i+1;j<=n;j++) 24 { 25 dp[0][i][j]=min(dp[0][i+1][j]+(x[i+1]-x[i])*(n-j+i), 26 dp[1][i+1][j]+(x[j]-x[i])*(n-j+i)); 27 dp[1][i][j]=min(dp[1][i][j-1]+(x[j]-x[j-1])*(n-j+i), 28 dp[0][i][j-1]+(x[j]-x[i])*(n-j+i)); 29 } 30 printf("%d\n",min(dp[0][1][n],dp[1][1][n])); 31 return 0; 32 }
