读入优化
无负数：
1 inline int nextInt() { 2 char c; 3 while (c = getchar(), c < '0' || c > '9'); 4 int r = c - '0'; 5 while (c = getchar(), c >= '0' && c <= '9') r = r * 10 + c - '0'; 6 return r; 7 }
有负数：
1 void scanf ( int& x , char c = 0 , int flag = 0 ) { 2 while ( ( c = getchar () ) != '-' && ( c < '0' || c > '9' ) ) ; 3 if ( c == '-' ) flag = 1 , x = 0 ; 4 else x = c - '0' ; 5 while ( ( c = getchar () ) >= '0' && c <= '9' ) x = x * 10 + c - '0' ; 6 if ( flag ) x = -x ; 7 }
