比如a[]={2,4,5,6,7},得出的两组数｛2，4，6｝和｛5，7｝，abs(sum(a1)-sum(a2))=0；
比如｛2，5，6，10｝，abs（sum(2,10)-sum(5,6))=1,所以得出的两组数分别为｛2，10｝和｛5，6｝。
vector<int> vct;
int last = INT_MAX;
int halfOfSum(int* arr, int len) {
int sum = 0;
for (int i = 0; i < len; ++i) {
sum += arr[i];
}
return sum / 2;
}
void difPrint(int* arr, int len, vector<int> vct) {
for (int i = 0; i < vct.size(); ++i) {
cout << vct[i] << " ";
}
cout << endl;
int vid = 0;
for (int i = 0; i < len; ++i) {
if (vct[vid] == arr[i]) {
vid++;
continue;
} else {
cout << arr[i] << " ";
}
}
cout << endl << endl;
}
void findCloestSequence(int* arr, int len, int step, int cur, vector<int> v) {
if (!arr || !len || cur < 0 || step == len) {
return;
} else if (cur < last) {
last = cur;
vct = v;
if (!last) {
return;
}
}
v.push_back(arr[step]);
findCloestSequence(arr, len, step + 1, cur - arr[step], v);
v.pop_back();
findCloestSequence(arr, len, step + 1, cur, v);
}