Compilare: user.cpp: In function ‘void backtracking(int)’: user.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= nr; i++) ^ user.cpp: In function ‘int main()’: user.cpp:65:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= t; i++) ^ user.cpp:69:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j <= k; j++) ^ user.cpp:71:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p[j] > b) ^ user.cpp:82:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int x = 1; x <= nr; x++) ^ user.cpp:88:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int l = 1; l <= nr; l++) ^