poj1877
注意要用c++,精度问题
注意有负数答案
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#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
using namespace std;
#define maxn 35
#define eps 10e-9
int map[maxn * maxn];
int n, m;
double water, least;
int dblcmp(double a, double b)
{
if (fabs(a - b) < eps)
return 0;
if (a < b)
return -1;
return 1;
}
void input()
{
least = 0x3f3f3f3f;
for (int i = 0; i < n * m; i++)
{
scanf("%d", &map[i]);
least = _cpp_min(least, double(map[i]));
}
scanf("%lf", &water);
}
bool high(double a)
{
double sum = 0;
for (int i = 0; i < n * m; i++)
if (dblcmp(map[i], a) < 0)
sum += (a - map[i]) * 100;
return sum > water;
}
double binarysearch()
{
double l = least;
double r = water;
while (dblcmp(l, r) < 0)
{
double mid = (l + r) / 2;
if (high(mid))
r = mid;
else
l = mid;
}
return l;
}
int main()
{
//freopen("t.txt", "r", stdin);
int t = 0;
while (scanf("%d%d", &n, &m), n | m)
{
t++;
input();
int a = 0;
double ans = binarysearch();
for (int i = 0; i < n * m; i++)
if (map[i] < ans)
a++;
printf(
"Region %d\nWater level is %.2f meters.\n%.2f percent of the region is under water.\n\n",
t, ans, a * 100.0 / n / m);
}
return 0;
}