foo.cc: In function 'int IN()':
foo.cc:13:1: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
 while (!isdigit(c=getchar()));x=c-'0';
 ^~~~~
foo.cc:13:31: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
 while (!isdigit(c=getchar()));x=c-'0';
                               ^
foo.cc:14:1: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
 while (isdigit(c=getchar())) x=(x<<1)+(x<<3)+c-'0';return x;
 ^~~~~
foo.cc:14:52: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
 while (isdigit(c=getchar())) x=(x<<1)+(x<<3)+c-'0';return x;
                                                    ^~~~~~
foo.cc: In function 'int main()':
foo.cc:7:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
 #define Mid (L+R>>1)
              ~^~
foo.cc:88:24: note: in expansion of macro 'Mid'
 while (L<=R) if (Check(Mid)) res=Mid,R=Mid-1;else L=Mid+1;
                        ^~~
foo.cc:7:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
 #define Mid (L+R>>1)
              ~^~
foo.cc:88:34: note: in expansion of macro 'Mid'
 while (L<=R) if (Check(Mid)) res=Mid,R=Mid-1;else L=Mid+1;
                                  ^~~
foo.cc:7:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
 #define Mid (L+R>>1)
              ~^~
foo.cc:88:40: note: in expansion of macro 'Mid'
 while (L<=R) if (Check(Mid)) res=Mid,R=Mid-1;else L=Mid+1;
                                        ^~~
foo.cc:7:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
 #define Mid (L+R>>1)
              ~^~
foo.cc:88:53: note: in expansion of macro 'Mid'
 while (L<=R) if (Check(Mid)) res=Mid,R=Mid-1;else L=Mid+1;
                                                     ^~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。