记录编号	201173	评测结果	AAAAAAAAAA
题目名称	护卫队	最终得分	100
用户昵称	旧梦	是否通过	通过
代码语言	C++	运行时间	0.022 s
提交时间	2015-10-30 06:35:41	内存使用	0.41 MiB

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<queue>
#include<algorithm>
#define LL long long
using namespace std;
const int maxn=1010;
int l,n,s[maxn];
LL w[maxn],rmq[maxn][15],sum[maxn],tot;
double dp[maxn];

void RMQ_init(){
	for (int i=0;i<=n;++i) rmq[i][0]=s[i];
	for (int j=1;(1<<j)<=n;++j)
	   for (int i=0;i+(1<<j)-1<=n;++i)
		   rmq[i][j]=min(rmq[i][j-1],rmq[i+(1<<j-1)][j-1]);
}

int RMQ(int l,int r){
	int k=0;
	while ((1<<k+1)<=r-l+1) k++;
	return min(rmq[l][k],rmq[r-(1<<k)+1][k]);
}

int main(){
	freopen("convoy.in","r",stdin);
	freopen("convoy.out","w",stdout);
	scanf("%lld%d%d",&tot,&l,&n);
	for (int i=1;i<=n;++i){
		scanf("%lld%d",&w[i],&s[i]);
		sum[i]=sum[i-1]+w[i];
	}
	s[0]=1000000000;
	RMQ_init();
	for (int i=1;i<=n;++i) dp[i]=10000000000000;
	dp[1]=(double)l/s[1]; dp[0]=0;
	for (int i=2;i<=n;++i)
	   for (int j=i;j>=1;--j){
			LL we=sum[i]-sum[j-1];
			if (we>tot) break;
			int tmp=RMQ(j,i);
			double tim=(double)l/tmp;
			dp[i]=min(dp[i],dp[j-1]+tim);
	   }
	printf("%.1lf",dp[n]*60);
	//system("pause");
}