poj1857 To Europe! To Europe!

思路：

一维dp。

实现：

#include <cstdio>
#include <iostream>
using namespace std;
const int INF = 0x3f3f3f3f;
int w[1005], v[1005], sum[1005];
double dp[1005];
int main()
{
    int b, l, n;
    while (cin >> b >> l >> n, b || l || n)
    {
        for (int i = 1; i <= n; i++) dp[i] = INF;
        for (int i = 1; i <= n; i++)
        {
            cin >> w[i] >> v[i];
            sum[i] = sum[i - 1] + w[i];
        }
        dp[1] = (double)l / v[1];
        for (int i = 2; i <= n; i++)
        {
            int minn = v[i];
            for (int j = i; j >= 1; j--)
            {
                if (sum[i] - sum[j - 1] > b) continue;
                minn = min(minn, v[j]);
                dp[i] = min(dp[i], dp[j - 1] + (double)l / minn);
            }
        }
        printf("%.1f\n", dp[n] * 60);
    }
    return 0;
}