【Codeforces 776B】Sherlock and his girlfriend

【题目链接】

点击打开链接

【算法】

将所有质数染成1，合数染成2即可

【代码】

#include<bits/stdc++.h>
using namespace std;
#define MAXN 100000

int i,N,x;
bool b1,b2;
int b[MAXN+];

template <typename T> inline void read(T &x) {
        int f=; x=;
        char c = getchar();
        for (; !isdigit(c); c = getchar()) { if (c == '-') f = -f; }
        for (; isdigit(c); c = getchar()) x = x *  + c - '';
        x *= f;
}

template <typename T> inline void write(T x) {
    if (x < ) { putchar('-'); x = -x; }
    if (x > ) write(x/);
    putchar(x%+'');
}

template <typename T> inline void writeln(T x) {
    write(x);
    puts("");
}

inline bool prime(int x) {
        int i;
        if (x == ) return false;
        for (i = ; i <= sqrt(x); i++) {
                if (!(x % i))
                        return false;
        }
        return true;
}

int main() {

        read(N);
        for (i = ; i <= N + ; i++) {
                b[i] = prime(i);
                if (b[i]) b1 = true;
                else b2 = true;
        }
        if (b1 && b2) puts("");
        else puts("");

        for (i = ; i <= N + ; i++) {
                if ((b1 && !b2) || (!b1 && b2)) write();
                else write(b[i]?:);
                if (i <= N) putchar(' ');
        }
        puts("");

        return ;

}