簡單幾何題，但是容易WA。做法是二分水面高度，然后看看這個高度對應多少水。
/**//*************************************************************************
Author: WHU_GCC
Created Time: 2007-9-5 20:34:00
File Name: pku1434.cpp
Description:
************************************************************************/
#include <iostream>
using namespace std;
#define out(x) (cout << #x << ": " << x << endl)
typedef long long int64;
const int maxint = 0x7FFFFFFF;
const int64 maxint64 = 0x7FFFFFFFFFFFFFFFLL;
template <class T> void show(T a, int n) 
{ for (int i = 0; i < n; ++i) cout << a[i] << ' '; cout << endl; }
template <class T> void show(T a, int r, int l) { for (int i = 0; i < r; ++i) show(a[i], l); cout << endl; }
const int maxn = 50010;
const double eps = 1e-3;
typedef struct tank_t
{
int b, h, w, d;
};
int n;
tank_t tank[maxn];
double water;
int ok(double mid)
{
double sum = 0.0;
for (int i = 0; i < n; i++)
{
if (tank[i].b < mid && mid < tank[i].b + tank[i].h)
sum += tank[i].w * tank[i].d * (mid - tank[i].b);
if (tank[i].b + tank[i].h <= mid)
sum += tank[i].w * tank[i].d * tank[i].h;
}
return sum < water;
}
double solve()
{
double up = 0.0, down = 1e10;
for (int i = 0; i < n; i++)
{
up >?= tank[i].b + tank[i].h;
down <?= tank[i].b;
}
if (ok(up))
return -1;
double mid;
while (up - down > eps)
{
mid = (up + down) / 2.0;
if (ok(mid))
down = mid;
else
up = mid;
}
if (ok(down))
return down;
else
return up;
}
int main()
{
int ca;
for (scanf("%d", &ca); ca--;)
{
scanf("%d", &n);
for (int i = 0; i < n; i++)
scanf("%d%d%d%d", &tank[i].b, &tank[i].h, &tank[i].w, &tank[i].d);
scanf("%lf", &water);
double ans = solve();
if (ans < 0)
printf("OVERFLOW\n");
else
printf("%.2lf\n", ans);
}
return 0;
}