[c++ IO加速]快速输入输出

自己封装的FastIO类，效率虽有所损失，不过实用性提高很多。

测试，写10000000个整数(86M)：

• printf 2.7s
• cout 27s
• FastIO 1s

测试，读10000000个整数(86M)：

• scanf 1.8s
• cin 15s
• FastIO 1s

 　　　　　　

利用c++的可变参数模板(c++11)和重载可以轻松实现数量不定的混合输入输出。

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class FastIO { public: FastIO() { pin = in; countin = countout = 0; } int read2mem() { return countin = fread(in, 1, insize, stdin); fclose(stdin); } int write2disk() { return fwrite(out, 1, countout, stdout); fclose(stdout); } int read() { return 0; } template<typename T, typename ...R> int read(T &f, R &...r) { if (get(f) == -1) return -1; c = read(r...); if (c == -1) return -1; return 1 + c; } void write() { put(' '); } template<typename T, typename ...R> void write(const T x, const R ...r) { put(x); write(r...); } private: const static int insize = (1 << 20) * 200, outsize = (1 << 20) * 100; char in[insize], out[outsize], *pin; int countin, countout, a[20], c, negative; /*** read ***/ inline bool digit(const char ch) { return ch == '-' || ch >= '0' && ch <= '9'; } int get(char s[]) { while ((*pin == ' ' || *pin == ' ') && pin - in != countin) pin ++; if (pin - in == countin) return -1; while (*pin != ' ' && *pin != ' ' && pin - in != countin) *s ++ = *pin ++; *s = 0; return 1; } int get(char &ch) { if (pin - in == countin) return -1; ch = *pin ++; return 1; } int get(int &buf) { while (!digit(*pin) && pin - in != countin) pin ++; if (pin - in == countin) return -1; buf = 0; negative = 0; if (*pin == '-') { negative = 1; pin ++; } while (digit(*pin) && pin - in != countin) { buf = buf * 10 + *pin - '0'; pin ++; } if (negative) buf = -buf; return 1; } /*** write ***/ void put(unsigned int x) { c = 0; a[c ++] = x % 10 + '0'; x /= 10; while (x) { a[c ++] = x % 10 + '0'; x /= 10; } while (c) { out[countout ++] = a[-- c]; } } void put(int x) { c = 0; negative = x < 0; if (negative) { x = -x; out[countout ++] = '-'; } a[c ++] = x % 10 + '0'; x /= 10; while (x) { a[c ++] = x % 10 + '0'; x /= 10; } while (c) { out[countout ++] = a[-- c]; } } void put(const char &ch) { out[countout ++] = ch; } void put(char s[]) { while (*s) out[countout ++] = *s ++; } };