[转]数据输入加速
转自:http://blog.csdn.net/shahdza/article/details/6317011
①
//适用于正整数 template <class T> inline void scan_d(T &ret) { char c; ret=0; while((c=getchar())<'0'||c>'9'); while(c>='0'&&c<='9') ret=ret*10+(c-'0'),c=getchar(); }
②
//适用于正负整数 template <class T> inline bool scan_d(T &ret) { char c; int sgn; if(c=getchar(),c==EOF) return 0; //EOF while(c!='-'&&(c<'0'||c>'9')) c=getchar(); sgn=(c=='-')?-1:1; ret=(c=='-')?0:(c-'0'); while(c=getchar(),c>='0'&&c<='9') ret=ret*10+(c-'0'); ret*=sgn; return 1; }
③
//适用于正负数,(int,long long,float,double) template <class T> bool scan_d(T &ret){ char c; int sgn; T bit=0.1; if(c=getchar(),c==EOF) return 0; while(c!='-'&&c!='.'&&(c<'0'||c>'9')) c=getchar(); sgn=(c=='-')?-1:1; ret=(c=='-')?0:(c-'0'); while(c=getchar(),c>='0'&&c<='9') ret=ret*10+(c-'0'); if(c==' '||c=='\n'){ ret*=sgn; return 1; } while(c=getchar(),c>='0'&&c<='9') ret+=(c-'0')*bit,bit/=10; ret*=sgn; return 1; }
inline void out(int x) { if(x>9) out(x/10); putchar(x%10+'0'); }
调用 scan_d(n) 对输入数据比较多的题目,有非常明显的加速效果!!!