Codeforces 460D Little Victor and Set(看题解)

Little Victor and Set

其他都很好求， 只有k == 3的时候很难受。。

我们找到第一个不大于l的 t， 答案为 l, 3 * t, (3 * t) ^ l

感觉好像是对的， 感觉又不会证明， 啊， 我好菜啊。

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define ull unsigned long long

using namespace std;

const int N = 5e5 + ;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + ;
const double eps = 1e-;
const double PI = acos(-);

LL l, r, k;

void print(LL x, int cnt) {
    if(!cnt) return;
    print(x / , cnt - );
    printf("%d", x & );
}

int main() {
    scanf("%lld%lld%lld", &l, &r, &k);
    LL n = r - l + ;
    if(k == ) {
        printf("%lld\n", l);
        puts("");
        printf("%lld\n", l);
    } else if(k == ) {
        if(n == ) {
            if(l < (l ^ r)) {
                printf("%lld\n", l);
                puts("");
                printf("%lld\n", l);
            } else {
                printf("%lld\n", l ^ r);
                puts("");
                printf("%lld %lld\n", l, r);
            }
        } else {
            if(l & ) {
                printf("%lld\n", (l + ) ^ (l + ));
                puts("");
                printf("%lld %lld\n", (l + ), (l + ));
            } else {
                printf("%lld\n", l ^ (l + ));
                puts("");
                printf("%lld %lld\n", l, (l + ));
            }
        }
    } else if(k == ) {
        LL t = ;
        while(t *  <= l) t *= ;
        if(t *  <= r) {
            puts("");
            puts("");
            printf("%lld %lld %lld\n", l,  * t, ( * t) ^ l);
        } else {
            puts("");
            puts("");
            if(l & ) printf("%lld %lld\n", l + , l + );
            else printf("%lld %lld\n", l, l + );
        }
    } else {
        if(l & ) {
            if(n >= ) {
                puts("");
                puts("");
                for(LL i = l + ; i < l + ; i++)
                    printf("%lld ", i);
                puts("");
            } else {
                for(int S = ; S < ( << n); S++) {
                    vector<LL> vc;
                    LL val = ;
                    for(int i = ; i < n; i++)
                        if(S >> i & ) val ^= l + i, vc.push_back(l + i);
                    if(!val) {
                        puts("");
                        printf("%d\n", SZ(vc));
                        for(auto& t : vc) printf("%lld ", t);
                        puts("");
                        return ;
                    }
                }
                puts("");
                puts("");
                printf("%lld %lld\n", l + , l + );
            }
        } else {
            puts("");
            puts("");
            for(LL i = l; i < l + ; i++)
                printf("%lld ", i);
            puts("");
        }
    }
    return ;
}

/*
*/