rainbow.cpp: In function 'void solve()':
rainbow.cpp:91:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d %d", &n, &m, &k);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
rainbow.cpp:95:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &buy[i][j], &sell[i][j]);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
rainbow.cpp:107:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d %d", &u, &v, &w);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/tmp/cca5nfJ2.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccrNjzje.o:rainbow.cpp:(.text.startup+0x0): first defined here
/tmp/cca5nfJ2.o: In function `main':
grader.cpp:(.text.startup+0xcc): undefined reference to `init(int, int, int, int, int, char*)'
grader.cpp:(.text.startup+0x131): undefined reference to `colour(int, int, int, int)'
collect2: error: ld returned 1 exit status