Method init

Data Structures/Interval Set.cpp:10–12

  map<pair<int, int>, T> value;//{r,l}=val

  void init(int n) {
    value[ {n, 1}] = (T)0;    //initial value
  }
  //assign a[i]=val for l<=i<=r
  //returns affected ranges before performing this assign operation
  vector<pair<pair<int, int>, T> > assign(int l, int r, T val) {