Battle Ships is a new game which is similar to Star Craft. In this game, the enemy builds a defense tower, which has L longevity. The player has a military factory, which can produce N kinds of battle ships. The factory takes ti seconds to produce the i-th battle ship and this battle ship can make the tower loss li longevity every second when it has been produced. If the longevity of the tower lower than or equal to 0, the player wins. Notice that at each time, the factory can choose only one kind of battle ships to produce or do nothing. And producing more than one battle ships of the same kind is acceptable. Your job is to find out the minimum time the player should spend to win the game. Input There are multiple test cases. Output Output one line for each test case. An integer indicating the minimum time the player should spend to win the game. Sample Input 1 1 1 1 2 10 1 1 2 5 3 100 1 10 3 20 10 100 Sample Output 2 4 5 Author: FU, Yujun Contest: ZOJ Monthly, July 2012 |
有n个塔和一个L血的怪物,制造一个塔需要t【i】时间,制造完成之后每秒对怪物造成L【i】血。问最少需要多少时间能消灭怪物。
#include<bits/stdc++.h>
using namespace std;
int t[1000];
int l[1000];
int dp[1000];
int main()
{
int n,L;
while(scanf("%d%d",&n,&L)!=EOF)
{
int i,j;
for(i=1;i<=n;i++)
cin>>t[i]>>l[i];
memset(dp,0,sizeof(dp));
for(j=1;j<=L;j++)
{
for(i=1;i<=n;i++)
{
dp[j+t[i]]=max(dp[j+t[i]],dp[j]+l[i]*j);
}
}
for(i=1;i<=400;i++)
{
if(dp[i]>=L)
{
break;
}
}
cout<<i<<endl;
}
return 0;
}