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A Wallet Exchange ↗#

题目大意#

Alice有a个硬币,Bob有b个硬币,双方轮流进行以下操作: 1.与对方交换硬币,或者保留现有硬币. 2.取出一个硬币无法进行操作的人判定为输,总是从Alice开始操作问:哪位获得胜利

解题思路#

我们可以把游戏看作是轮流取硬币,取得最后一个硬币的为胜利那么我们就可以直接判断a+b奇偶性就可以得出答案.

代码#

#include <bits/stdc++.h>

#define int long long
#define endl '\n'
#define fix(n) std::fixed << std::setprecision(n)
[[maybe_unused]]typedef std::pair<int, int> pii;
[[maybe_unused]]const int INF = 1e18 + 50;

void solve() {
    int a, b;
    std::cin >> a >> b;
    std::cout << ((a + b) % 2 ? "Alice" : "Bob") << endl;
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr), std::cout.tie(nullptr);
    int Lazy_boy_ = 1;
    std::cin >> Lazy_boy_;
    while (Lazy_boy_--)
        solve();
    return 0;
}

cpp

B Plus-Minus Split ↗#

题目大意#

略

解题思路#

简单看下样例就猜出来是+与-的差值的绝对值

代码#

#include <bits/stdc++.h>

#define int long long
#define endl '\n'
#define fix(n) std::fixed << std::setprecision(n)
[[maybe_unused]]typedef std::pair<int, int> pii;
[[maybe_unused]]const int INF = 1e18 + 50;

void solve() {
    int n;
    std::string s;
    std::cin >> n >> s;
    int cnt1 = 0;
    for (auto i: s)
        cnt1 += (i == '+');
    std::cout << abs((n - cnt1) - cnt1) << endl;
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr), std::cout.tie(nullptr);
    int Lazy_boy_ = 1;
    std::cin >> Lazy_boy_;
    while (Lazy_boy_--)
        solve();
    return 0;
}

cpp

C Grouping Increases ↗#

题目大意#

解题思路#

贪心

代码#

#include <bits/stdc++.h>

#define int long long
#define endl '\n'
#define fix(n) std::fixed << std::setprecision(n)
[[maybe_unused]]typedef std::pair<int, int> pii;
[[maybe_unused]]const int INF = 1e18 + 50;

void solve() {
    int n, ans = 0;
    std::cin >> n;
    std::vector<int> a(n, 0ll);
    for (int i = 0; i < n; i++) std::cin >> a[i];
    std::vector<int> A, B;
    A.push_back(INF), B.push_back(INF);
    for (int i = 0; i < n; i++) {
        int x = A.back(), y = B.back();
        if (x < y) {
            if (a[i] <= x)
                A.push_back(a[i]);
            else if (a[i] <= y)
                B.push_back(a[i]);
            else {
                A.push_back(a[i]);
                ans++;
            }
        } else {
            if (a[i] <= y)
                B.push_back(a[i]);
            else if (a[i] <= x)
                A.push_back(a[i]);
            else {
                B.push_back(a[i]);
                ans++;
            }
        }
    }
    std::cout << ans << endl;
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr), std::cout.tie(nullptr);
    int Lazy_boy_ = 1;
    std::cin >> Lazy_boy_;
    while (Lazy_boy_--)
        solve();
    return 0;
}

cpp