Compilare: main.cpp: In function 'void heapify(int)': main.cpp:43:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (l < heap.size() && heap[l].y < heap[i].y) ~~^~~~~~~~~~~~~ main.cpp:50:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (r < heap.size() && (heap[r].y < heap[i].y&&heap[r].y<heap[l].y)) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:100:9: warning: unused variable 'i' [-Wunused-variable] int i=0; ^