Time Lapse :20min 0sec

solution.cpp

#include <vector>
using namespace std;
int NUM[20],tot = 0,T, size;
//20:00 
vector<int> DP(1048576,-1);
int dp(int idx,int bit_mask){
    if(idx==size)
        return 0;
    if(DP[bit_mask]!=-1)
        return DP[bit_mask];
    if(bit_mask&1<<idx){
        DP[bit_mask] = dp(idx+1,bit_mask^1<<idx) - 2*NUM[idx];
        return DP[bit_mask];
    }
    return dp(idx+1,bit_mask);
}

int DFS(int idx,int bit_mask){
    if(idx==size){
        if(T == tot + dp(0,bit_mask))
            return 1;
        return 0;
    }
    return DFS(idx+1,bit_mask)+DFS(idx+1,bit_mask|1<<idx);
}

int solution(vector<int> numbers, int target) {
    T = target; size = numbers.size();
    for(int i=0;i<numbers.size();i++)
        tot += NUM[i] = numbers[i];
    return DFS(0,0);
}

/*
 * 포인터 처리
 #include <vector>
 using namespace std;
 vector<int> *NUM;
 int *Target;
 int answer;
 void DFS(int sum,int n) {
 if(n >= NUM->size()){
 if(sum == *Target) answer++;
 return;
 }
 DFS(sum , n+1);
 DFS(sum - NUM->at(n)*2, n+1);
 }
 int solution(vector<int> numbers, int target) {
 int total = 0;
 for(int i=0;i<numbers.size();i++)
 total += numbers[i];
 NUM = &numbers;
 Target = &target;
 DFS(total , 1);
 DFS(total-2*numbers[0], 1);
 return answer;
 }
 */