vector<vector<int> > fourSum(vector<int> &num, int target) {
// wyuan; 10/15/2014; This is very similar with "Combination Sum II"
sort(num.begin(), num.end());
// !!! So careless. Not 0, but target!
// return kSum(num, 0, 4, 0);
return kSum(num, 0, 4, target); // use the same code with 3Sum.
}
vector<vector<int> > kSum(const vector<int> &num, int begin, int count, int target)
{
vector<vector<int> > res;
if(count < 2)
return res;
set<int> visited;
if(count == 2)
{
return twoSum(num, begin, target);
}
else
{
int size = num.size();
for(int i = begin; i<size; i++)
{
if(visited.find(num[i]) != visited.end())
continue;
visited.insert(num[i]);
vector<vector<int> > subRes = kSum(num, i+1, count-1, target-num[i]);
if(!subRes.empty())
{// we can pass num[i] to kSum, instead of inserting it here.
int subSize = subRes.size();
for(int j=0; j < subSize; j++)
{
subRes[j].insert(subRes[j].begin(), num[i]);
}
res.insert(res.end(), subRes.begin(), subRes.end());
}
}
}
return res;
}
vector<vector<int> > fourSum(vector<int> &num, int target) {
// IMPORTANT: Please reset any member data you declared, as
// the same Solution instance will be reused for each test case.
vv.clear();
sort(num.begin(), num.end());
vector<int> tmp;
kSum(num, target, 4, 0, tmp);
return vv;
}
moDMatrix<Real> moDMatrix<Real>::operator+ (const moDMatrix& rkM) const
{
moDMatrix<Real> kSum(rkM.m_iRows,rkM.m_iCols);
for (int i = 0; i < m_iQuantity; i++)
{
kSum.m_afData[i] = m_afData[i] + rkM.m_afData[i];
}
return kSum;
}
PolyBase PolyBase::operator/(const double V) const
/**
PolyBase division
@param V :: Value division
@return (*this/V);
*/
{
PolyBase kSum(*this);
return kSum /= V;
}
PolyBase PolyBase::operator*(const double V) const
/**
PolyBase multiplication
@param V :: Value multiplication
@return (*this*V);
*/
{
PolyBase kSum(*this);
return kSum *= V;
}
PolyBase PolyBase::operator-(const double V) const
/**
PolyBase substractr
@param V :: Value substract
@return (*this-V);
*/
{
PolyBase kSum(*this);
return kSum -= V;
}
PolyBase PolyBase::operator+(const double V) const
/**
PolyBase addition
@param V :: Value Addtion
@return (*this+V);
*/
{
PolyBase kSum(*this);
return kSum += V;
}
PolyBase PolyBase::operator*(const PolyBase &A) const
/**
PolyBase multiplication
@param A :: PolyBase multiplication
@return (*this*A);
*/
{
PolyBase kSum(*this);
return kSum *= A;
}
PolyBase PolyBase::operator-(const PolyBase &A) const
/**
PolyBase subtraction
@param A :: PolyBase addition
@return (*this-A);
*/
{
PolyBase kSum(*this);
return kSum -= A;
}
PolyBase PolyBase::operator+(const PolyBase &A) const
/**
PolyBase addition
@param A :: PolyBase addition
@return (*this+A);
*/
{
PolyBase kSum(*this);
return kSum += A;
}
void kSum(vector<int> &a, int target, int k, int index, vector<int> &helper) {
int sz = a.size();
if(k > sz - index)
return;
if(k == 1) {
int pos = binarySearch(a, index, sz - 1, target);
if(pos != -1) {
helper.push_back(a[pos]);
vv.push_back(helper);
helper.pop_back();
}
return;
}
for(int i = index; i <= sz - k; ++i) {
if(i != index && a[i] == a[i-1])
continue;
helper.push_back(a[i]);
kSum(a, target - a[i], k - 1, i + 1, helper);
helper.pop_back();
}
}