Compilare: user.c: In function ‘main’: user.c:71:5: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(tr, 0, sizeof tr); ^ user.c:71:5: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:47:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d ", &n, &m); ^