Compilare: main.cpp: In function 'int main()': main.cpp:77:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(px2 > sx.size()) --px2; ~~~~^~~~~~~~~~~ main.cpp:79:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(px3 > sx.size()) --px3; ~~~~^~~~~~~~~~~ main.cpp:82:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(py2 > sy.size()) --py2; ~~~~^~~~~~~~~~~ main.cpp:84:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(py3 > sy.size()) --py3; ~~~~^~~~~~~~~~~ main.cpp:76:13: warning: unused variable 'val' [-Wunused-variable] int val = sx[px2 - 1]; ^~~ main.cpp:25:9: warning: unused variable 'NR' [-Wunused-variable] int NR = 0; ^~ main.cpp:20:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("agora.in", "r", stdin); ^ main.cpp:21:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("agora.out", "w", stdout); ^ main.cpp:23:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &q); ^ main.cpp:64:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &x, &y, &x2, &y2); ^