Codeforces Round #646 (Div. 2)

题目传送门

先放这，后面会补的

A. Odd Selection

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, a, b) for (register int i = a; i <= b; i++)

int x, n, a[1010];
int even, odd;
void solve()
{
    cin >> n >> x;
    odd = even = 0;
    rep(i, 1, n)
    {
        cin >> a[i];
        if (a[i] % 2)
            odd++;
        else
            even++;
    }
    int flag = 1;
    if (x == n && odd % 2 == 0)
        flag = 0;
    if (odd == 0)
        flag = 0;
    if ((x - 1) % 2 && even == 0)
        flag = 0;
    puts(flag ? "Yes" : "No");
}
int main()
{
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
}

B. Subsequence Hate

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, a, b) for (register int i = a; i <= b; i++)

char s[1010];
int n, dp[2][1010];
int ans;
void solve()
{
    memset(s, 0, sizeof(s));
    cin >> s + 1;
    n = 0;
    for (int i = 1; s[i] != 0; i++)
    {
        n++;
        dp[0][i] = dp[0][i - 1];
        dp[1][i] = dp[1][i - 1];
        if (s[i] == '1')
            dp[0][i]++;
        if (s[i] == '0')
            dp[1][i]++;
    }
    ans = min(dp[0][n], dp[1][n]);
    for (int i = 1; s[i] != 0; i++)
    {
        ans = min(ans, dp[0][i] + dp[1][n] - dp[1][i]);
        ans = min(ans, dp[1][i] + dp[0][n] - dp[0][i]);
    }
    cout << ans << endl;
}
int main()
{
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
}

C. Game On Leaves

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, a, b) for (register int i = a; i <= b; i++)

int n, x;
int u, v, cnt;
void solve()
{
    cin >> n >> x;
    cnt = 0;
    rep(i, 1, n - 1)
    {
        cin >> u >> v;
        if (u == x || v == x)
            cnt++;
    }
    if (cnt <= 1 || !(n & 1))
        puts("Ayush");
    else
        puts("Ashish");
}
int main()
{
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
}