HDU 5308 I Wanna Become A 24-Point Master（2015多校第二场）

I Wanna Become A 24-Point Master

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 485 Accepted Submission(s): 191
Special Judge

Problem Description

Recently Rikka falls in love with an old but interesting game -- 24 points. She wants to become a master of this game, so she asks Yuta to give her some problems to practice.

Quickly, Rikka solved almost all of the problems but the remained one is really difficult:

In this problem, you need to write a program which can get 24 points with

numbers, which are all equal to

Input

There are no more then 100 testcases and there are no more then 5 testcases with

. Each testcase contains only one integer

Output

For each testcase:

If there is not any way to get 24 points, print a single line with -1.

Otherwise, let

be an array with

numbers and at firsrt

. You need to print

lines and the

th line contains one integer

, one char

and then one integer c, where

and

is "+","-","*" or "/". This line means that you let

and

do the operation

and store the answer into

.

If your answer satisfies the following rule, we think your answer is right:

1.

2. Each position of the array

is used at most one tine.

3. The absolute value of the numerator and denominator of each element in array

is no more than

Sample Input

Sample Output

1 * 2
5 + 3
6 + 4

Source

2015 Multi-University Training Contest 2

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
using namespace std;
int N;
int main()
{
    while(scanf("%d", &N)!=EOF)
    {
        if(N == 1 || N == 2 || N == 3 ) printf("-1
");
        else if(N == 4)
        {
            printf("1 * 2
");
            printf("5 + 3
");
            printf("6 + 4
");
        }
        else if(N == 5)
        {
            printf("1 * 2
");//6  25
            printf("3 * 6
");//7  125
            printf("7 - 4
");//8  120
            printf("8 / 5
");//9  24
        }
        else if(N == 6)
        {
            printf("1 * 2
");//7  36
            printf("7 - 3
");//8  30
            printf("8 - 4
");//9  24
            printf("9 + 5
");//10 30
            printf("10 - 6
");//11 24
        }
        else if(N == 7)
        {
            printf("1 / 2
");//8  1
            printf("3 + 8
");//9 8
            printf("4 + 5
");//10 14
            printf("10 + 6
");//11 21
            printf("11 / 7
");//12 3
            printf("12 * 9
");//13 24
        }
        else if(N == 8)
        {
            printf("1 + 2
");//9  16
            printf("3 + 9
");//10 24
            printf("4 - 5
");//11 0
            printf("11 * 6
");//12 0
            printf("12 * 7
");//13 0
            printf("13 * 8
");//14 0
            printf("14 + 10
");//15 24
        }
        else if(N == 9)
        {
            printf("1 + 2
");//10   18
            printf("10 + 3
");//11  27
            printf("11 * 4
");//12  243
            printf("12 / 5
");//13  27
            printf("6 + 7
");//14   18
            printf("14 + 8
");//15  27
            printf("15 / 9
");//16  3
            printf("13 - 16
");//17 24
        }
        else if(N == 10)
        {
            printf("1 + 2
");//11   20
            printf("3 + 4
");//12   20
            printf("12 + 5
");//13  30
            printf("13 + 6
");//14  40
            printf("14 / 7
");//15  4
            printf("11 + 15
");//16 24
            printf("8 - 9
");//17   0
            printf("17 / 10
");//18 0
            printf("16 + 18
");//19 24
        }
        else if(N == 11)
        {
            printf("1 + 2
");//12  22
            printf("12 / 3
");//13 2
            printf("13 + 4
");//14 13
            printf("14 + 5
");//15 24
            printf("15 + 6
");//16 35
            printf("16 + 7
");//17 46
            printf("17 + 8
");//18 57
            printf("18 - 9
");//19 46
            printf("19 - 10
");//20 35
            printf("20 - 11
");//21 24
        }
        else if(N >= 12 && N % 2 == 0)
        {
            printf("1 + 2
");//N+1                  2*N
            printf("%d + 3
",N+1);//N+2             3*N
            printf("4 + 5
");//N+3                  2*N
            printf("%d + 6
",N+3);//N+4             3*N
            printf("%d + 7
",N+4);//N+5             4*N
            printf("8 + 9
");//N+6                  2*N
            printf("%d / 10
",N+2);//N+7            3
            printf("%d / 11
",N+5);//N+8            4
            printf("%d / 12
",N+6);//N+9            2
            printf("%d * %d
",N+7,N+8);//N+10       12
            printf("%d * %d
",N+9,N+10);//N+11      24
            for(int i=0;i<(N-12)/2;i++)
            {
                printf("%d + %d
",N+11+2*i,13+i*2);//N+12+2*i
                printf("%d - %d
",N+12+2*i,14+i*2);//N+13+2*i
            }
        }
        else if(N>=13 && N % 2 == 1)
        {
            printf("1 + 2
");//N+1               2*N
            printf("%d + 3
",N+1);//N+2          3*N
            printf("4 + 5
");//N+3               2*N
            printf("%d + 6
",N+3);//N+4          3*N
            printf("%d + 7
",N+4);//N+5          4*N
            printf("%d + 8
",N+5);//N+6          5*N
            printf("%d + 9
",N+6);//N+7          6*N
            printf("%d + 10
",N+7);//N+8         7*N
            printf("%d + 11
",N+8);//N+9         8*N
            printf("%d / 12
",N+2);//N+10        3
            printf("%d / 13
",N+9);//N+11        8
            printf("%d * %d
",N+10,N+11);//N+12  24
            for(int i=0;i<(N-13)/2;i++)
            {
                printf("%d + %d
",N+12+2*i,14+i*2);//N+13+2*i
                printf("%d - %d
",N+13+2*i,15+i*2);//N+14+2*i
            }

        }
    }
}