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[];
 int    b[];
 double c[];
 int n, k;
 double l, m, u;
 bool C(double m) {
     double sum = ;
     for (int i = ; 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\n", (int)(l*+0.5))) {//n = ?, k=0
         for (int i = ; i < n; scanf("%d", a+i)&&i++);
         for (int i = ; 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 ;
 }

　　听说还是典型的01整数规划，有时间试试！