Compilare: user.cpp: In function ‘int main()’: user.cpp:33:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(l+(1<<v[i].y)<=b) {l=l+(1<<v[i].y);cost=cost+v[i].x;if(cost>maxcost) {maxcost=cost;r=l;}} ^ user.cpp:38:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(l>b) ^ user.cpp:46:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(r>=a) printf("%lld\n",maxcost); ^ user.cpp:54:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(1<<v1[i].y>=r && r1+(1<<v1[i].y)<=b) {if(v1[i].x>costmin) costmin=v1[i].x;l=0;} ^ user.cpp:56:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(l+(1<<v1[i].y)<r && l+(1<<v1[i].y)<=b) {l=l+(1<<v1[i].y);cost=cost+v1[i].x;} ^ user.cpp:14:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bitcost.in","r",stdin); ^ user.cpp:15:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bitcost.out","w",stdout); ^ user.cpp:19:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&k,&m); ^ user.cpp:22:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:28:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&a,&b); ^