封装getchar/putchar的输入输出

template<typename T>
void read(T &x) {
    int f = 1;
    x = 0;
    char ch = getchar();
 while (ch < '0' || ch > '9') {
        if (ch == '-')f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9') {
        x = x * 10 + (ch ^ 48);
        ch = getchar();
    }
    x *= f;
}

template<typename T>
void print(T x) {
    if (x < 0) putchar('-'), x = -x;
    if (x > 9) print(x / 10);
    putchar(x % 10 + '0');
}

ACM赛制下的常规优化

#pragma GCC optimize(3)  
#include<bits/stdc++.h>  
#define endl "\n"
using namespace std;
using ll = long long;


int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    return 0;
}