Method swim

code/data-structures/heap.cpp:13–17

  inline void swp(int i, int j) {
    SWP(q[i], q[j]), SWP(loc[q[i]], loc[q[j]]); }
  void swim(int i) {
    while (i > 0) {
      int p = (i - 1) / 2;
      if (!cmp(i, p)) break;
      swp(i, p), i = p; } }
  void sink(int i) {
    while (true) {
      int l = 2*i + 1, r = l + 1;