CCPC2019-哈尔滨站

F. Fixing Banners

#include<bits/stdc++.h>

using namespace std;

const int N = 2e6 + 10;
int T, n = 6;
char s[6][N];
unordered_set<char> Set[6];
char g[7] = "harbin";
bool v[7];

bool check(int u) {
    if (u == n) return true;
    for (int i = 0; i < n; i++) {
        if (v[i]) continue;
        if (Set[i].count(g[u]) == 0) continue;
        v[i] = true;
        if (check(u + 1)) return true;
        v[i] = false;
    }

    return false;
}

int main() {
    cin >> T;
    while (T--) {
        memset(v, false, sizeof v);
        for (int i = 0; i < n; i++) Set[i].clear();
        for (int i = 0; i < n; i++) {
            scanf("%s", s[i]);
            int len = strlen(s[i]);
            for (int j = 0; j < len; j++) Set[i].insert(s[i][j]);
        }

        if (check(0)) puts("Yes");
        else puts("No");
    }
    return 0;
}

J. Justifying the Conjecture

#include<bits/stdc++.h>

using namespace std;

const int N = 1e6 + 5;
int T, n;

const int M = 1e6 + 5;
bool v[M];
vector<int> primes;

void calc_primes() {
    memset(v, true, sizeof(v));
    for (int i = 2; i < M; i++) {
        if (v[i]) {
            primes.push_back(i);
            for (int j = 2; j <= M / i; j++) v[i * j] = false;
        }
    }
}

bool check(int x) {
    for (int i:primes) {
        if (i * i > x) break;
        if (x % i == 0) return false;
    }
    return true;
}

int main() {
    cin >> T;
    calc_primes();
    while (T--) {
        scanf("%d", &n);
        bool st = false;
        for (int x:primes) {
            if (x >= n) break;
            int y = n - x;
            if (y > 1 && !check(y)) {
                printf("%d %d\n", x, y);
                st = true;
                break;
            }
        }
        if (!st) puts("-1");
    }
    return 0;
}

K. Keeping Rabbits

#include<bits/stdc++.h>

using namespace std;

const int N = 1e5 + 5;
int T, n, k, w[N];
typedef long long LL;

int main() {
    cin >> T;
    while (T--) {
        scanf("%d%d", &n, &k);
        LL s = 0;
        for (int i = 1; i <= n; i++) {
            scanf("%d", &w[i]);
            s += w[i];
        }

        for (int i = 1; i <= n; i++) {
            printf("%.5lf ", w[i] + w[i] * 1.0 / s * k);
        }
        puts("");
    }

    return 0;
}