Compilare: main.cpp: In function 'void down_heap()': main.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (2 * k + 1 <= heap.size() - 1) { ~~~~~~~~~~^~~~~~~~~~~~~~~~~~ main.cpp:24:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (2*k+2 <= heap.size()-1 && heap[2*k+2].s < heap[min_poz].s) { ~~~~~~^~~~~~~~~~~~~~~~ main.cpp:17:29: warning: unused variable 'le' [-Wunused-variable] int k = 0, min_poz = 0, le; ^~