General Initial 類
iota: 等價於range(<start>,<end>,1)，將 container element inplace 置換成等差數列
//v is vector with size 10
iota(v.begin(),v.end(),0); //v becomes [0,1,2,...,9]
fill,fill_n: 將 container element 置換成一定值
fill(v.begin(),v.end(),0); // v becomes [0,0,...,0]
fill_n(v.begin(),2,-1); // v becomes [-1,-1,0,...,0]
copy: 將[first,last) 的 element copy 到另一個 container
copy(from_vec.begin(),from_vec.end(),std::back_inserter(to_vec));
//equivalent，但to_vec size 需先 resize 好，否則會SIGSEV
copy(ALL(from_vec),to_vec.begin());
//Another easy way if want to copy **all** elements
vector<int> to_vec = from_vec;
vector<int> to_vec(from_vec)
Note: 不可用於 copy 者與被 copy 者範圍重疊。
generate:
計算類
partial_sum: 計算 [first,last) 的 prefix sum
partial_sum(fromvec.begin(),fromvec.end(),tovec.begin()) // [0,1,3,6,...,50]
//product [0!,1!,2!,3!,...,9!]
partial_sum(ALL(from_vec),tovec.begin(),std::multiplies<int>());
//custom lambda op
partial_sum(ALL(from_vec),tovec.begin(),[](int x,int y){return foo(x,y);});
Note: 如果 tovec 跟 fromvec 的 begin() 一樣的話，就是 inplace 置換。
- accumulate: 類似於找
partial_sum()的最後一個元素
//一樣可以與 lambda 做搭配
int sum = accumulate(ALL(vec),0); // 0 為基準值
random_shuffle: inplace shuffle elements
srand(unsigned time(NULL)); //rng initialzation
random_shuffle(vec.begin(),vec.end());// build-in rng
random_shuffle(vec.begin(),vec.end(),[](int n){return my_rand(n)};);// custom