201805牛客模拟考

第一题AC，注意点：输入是long类型，不能用BufferedReader，不然很麻烦：

public class Main {

    public static void main(String[] args) throws IOException {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        long f = in.nextLong();
        long d = in.nextLong();
        long p = in.nextLong();
        long last = d - x * f;
        if(last > 0) {
            long day = last / (x + p);
            System.out.println(day + f);
        }
        //如果钱还不够付初始房费的
        else {
            long day = d / x;
            System.out.println(day);
        }
    }

}

第二题过了60%，穷举所有可能性。先计算单独吃一盒三份、一盒两份和一盒一份可维持的天数，然后再将剩余的数量拼凑起来。不知道哪里错了。代码如下：

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        while(t-- != 0) {
            int n = in.nextInt();
            int a = in.nextInt();
            int b = in.nextInt();
            int c = in.nextInt();
            int day_c = c / 2, last_c = c % 2;
            int day_b = b / 3, last_b = b % 3;
            int day_a = a / 6, last_a = a % 6;
            int last = 0;
            //三份还剩一盒
            if(last_c == 1) {
                //两份还剩一盒
                if(last_b == 1) {
                    //3+2+1
                    if(last_a > 0) {
                        last = 1;
                    }
                }
                //两份还剩两盒
                else if(last_b == 2) {
                    //3+2+1
                    if(last_a > 0 && last_a < 5) {
                        last = 1;
                    }
                    //3+4+5
                    else if(last_a == 5) {
                        last = 2;
                    }
                }
                else {
                    //3+0+3
                    if(last_a >= 3) {
                        last = 1;
                    }
                }
            }
            else {
                //0+2+4
                if(last_b == 1) {
                    if(last_a >= 4) {
                        last = 1;
                    }
                }
                //0+4+2
                else if(last_b == 2) {
                    if(last_a >= 2) {
                        last = 1;
                    }
                }
            }
        //    System.out.println(day_c + "," + day_b + "," + day_a + "," + last);
            int day = day_c + day_b + day_a + last;
            if(day >= n) {
                System.out.println("Yes");
            }
            else {
                System.out.println("No");
            }
        }
    }
}

据说别人AC的思路，也是穷举，只是先单独吃一盒三份和一盒两份的，然后再将剩余的与一盒一份的进行拼凑，最后单独吃一盒一份的。代码如下：

public class Main2 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        while(t-- != 0) {
            int n = in.nextInt();
            int a = in.nextInt();
            int b = in.nextInt();
            int c = in.nextInt();
            int day_c = c / 2, last_c = c % 2;
            int day_b = b / 3, last_b = b % 3;
            int day = 0;
            //三份还剩一盒
            if(last_c == 1) {
                //两份还剩一盒
                if(last_b == 1) {
                    //3+2+1
                    if(a >= 1) {
                        day++;
                        a -= 1;
                    }
                }
                //两份还剩两盒
                else if(last_b == 2) {
                    //3+2+1
                    if(a >= 1 && a < 5) {
                        a -= 1;
                        day++;
                    }
                    //3+4+5
                    else if(a >= 5) {
                        a -= 5;
                        day += 2;
                    }
                }
                else {
                    //3+0+3
                    if(a >= 3) {
                        a -= 3;
                        day++;
                    }
                }
            }
            else {
                //0+2+4
                if(last_b == 1) {
                    if(a >= 4) {
                        a -= 4;
                        day++;
                    }
                }
                //0+4+2
                else if(last_b == 2) {
                    if(a >= 2) {
                        a -= 2;
                        day++;
                    }
                }
            }
            day = day + day_c + day_b + a / 6;
            if(day >= n) {
                System.out.println("Yes");
            }
            else {
                System.out.println("No");
            }
        }
    }

}