USER: Kevin Samuel [kevin_s1]
TASK: zerosum
LANG: C++

Compiling…
Compile: OK

Executing…
Test 1: TEST OK [0.003 secs, 3508 KB]
Test 2: TEST OK [0.003 secs, 3508 KB]
Test 3: TEST OK [0.005 secs, 3508 KB]
Test 4: TEST OK [0.000 secs, 3508 KB]
Test 5: TEST OK [0.005 secs, 3508 KB]
Test 6: TEST OK [0.008 secs, 3508 KB]
Test 7: TEST OK [0.014 secs, 3508 KB]

All tests OK.

YOUR PROGRAM ('zerosum') WORKED FIRST TIME! That's fantastic
-- and a rare thing. Please accept these special automated
congratulations.

Here are the test data inputs:

------- test 1 ----
3
------- test 2 ----
4
------- test 3 ----
5
------- test 4 ----
6
------- test 5 ----
7
------- test 6 ----
8
------- test 7 ----
9

Keep up the good work!

Thanks for your submission!

it's a easy problem of dfs

/*
ID:kevin_s1
PROG:zerosum
LANG:C++
*/

#include
#include
#include
#include
#include
#include

using namespace std;

//gobal variable====
int N;
vector result;
//==================

//function==========
char NumToChar(int i){
char ch = i + 48;
return ch;
}

void DFS(int i, int sum, string str, int last_operator){
if(i > N + 1)
return;
if(i == N + 1){
if(sum == 0){
result.push_back(str);
}
return;
}
//plus
string tmp1 = str;
tmp1 = tmp1 + "+" + NumToChar(i);
DFS(i + 1, sum + i, tmp1, i);
//minus
string tmp2 = str;
tmp2 = tmp2 + "-" + NumToChar(i);
DFS(i + 1, sum - i, tmp2, -i);
//multiply
string tmp3 = str;
tmp3 = tmp3 + " " + NumToChar(i);
int cc = 0;
if(last_operator > 0)
cc = 1;
else
cc = -1;
int mt = cc * (abs(last_operator) * 10 + i);
int sum_tmp = sum - last_operator + mt;
DFS(i + 1, sum_tmp, tmp3, mt);
return;
}

//==================

int main(){
freopen("zerosum.in","r",stdin);
freopen("zerosum.out","w",stdout);
cin>>N;
string str = "1";
DFS(2, 1, str, 1);
sort(result.begin(), result.end(), less());
vector::iterator iter;
for(iter = result.begin(); iter != result.end(); iter++){
cout<<*iter<<endl;
}
return 0;
}