POJ 2976 Dropping tests（最大化平均值 or 01整数规划）

题目链接

　　忽略运算符逻辑导致奇怪的错误（代码中指明位置了）

　　输出没加0.5，WA。

　　还有，注意特殊情况k=0,所以scanf("%d%d", &n, &k)&n就够了， scanf("%d%d", &n, &k)&n&k应该会WA。

#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;
int a[1005];
int    b[1005];
double c[1005];
int n, k;
double l, m, u; 
bool C(double m) {
    double sum = 0;
    for (int i = 0; i < n; i++) {
        c[i] = a[i] - b[i]*m;
    }
    sort(c, c+n);
    for (int i = k; i < n; i++) sum += c[i];
    //for (int i = k; i < n; sum += c[i] && i++); priority
    return sum >= 0.0;
}
int main(void) {
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    for (;scanf("%d%d", &n, &k) && n; printf("%d
", (int)(l*100+0.5))) {//n = ?, k=0
        for (int i = 0; i < n; scanf("%d", a+i)&&i++);
        for (int i = 0; i < n; scanf("%d", b+i)&&i++);
        l = 0.0, u = 1.0;
        for ( ;fabs(u-l) > 0.0001; ) {
            m = (u+l)/2.0;
            if (C(m)) l = m;
            else u = m;
        }
    }
    return 0;
}

　　听说还是典型的01整数规划，有时间试试！