blocks.cpp: In function 'int main()':
blocks.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
27 | freopen("input.txt", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
28 | freopen("output.txt", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:17:25: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
17 | #define scii(x, y) scanf("%d %d", &x, &y)
| ~~~~~^~~~~~~~~~~~~~~~~
blocks.cpp:31:5: note: in expansion of macro 'scii'
31 | scii(n, k);
| ^~~~
blocks.cpp:16:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
16 | #define sci(x) scanf("%d", &x)
| ~~~~~^~~~~~~~~~
blocks.cpp:32:18: note: in expansion of macro 'sci'
32 | fto(i, 1, n) sci(a[i]);
| ^~~