poj1877

注意要用c++，精度问题

注意有负数答案

View Code

#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;
}

转载于:https://www.cnblogs.com/rainydays/archive/2011/08/01/2123908.html