这种题的关键在于取走最后一个的获胜
因此就会交换先后手, 先手拿大于
的堆一定会获胜
根据
的奇偶性不同, 先手可以做如下操作
- 拿
个, 将
留给后手
- 直接拿
个
如果当前是奇数, 直接拿全部, 如果当前
是偶数, 拿
, 这样就会保证到最后一堆一定是先手拿
注意特殊处理全是的情况
#include <bits/stdc++.h>
#define x first
#define y second
#define all(x) x.begin(), x.end()
#define vec1(T, name, n, val) vector<T> name(n, val)
#define vec2(T, name, n, m, val) vector<vector<T>> name(n, vector<T>(m, val))
#define vec3(T, name, n, m, k, val) vector<vector<vector<T>>> name(n, vector<vector<T>>(m, vector<T>(k, val)))
#define vec4(T, name, n, m, k, p, val) vector<vector<vector<vector<T>>>> name((n), vector<vector<vector<T>>>((m), vector<vector<T>>((k), vector<T>((p), (val)))))
using namespace std;
using i128 = __int128;
using u128 = unsigned __int128;
using LL = long long;
using LD = long double;
using ULL = unsigned long long;
using PII = pair<int, int>;
using PLL = pair<LL, LL>;
using PLD = pair<LD, LD>;
const int N = 1e5 + 10, MOD = 998244353;
const int INF = 1e9;
const LL LL_INF = 1e18;
const LD EPS = 1e-8;
const int dx4[] = {-1, 0, 1, 0}, dy4[] = {0, 1, 0, -1};
const int dx8[] = {-1, -1, -1, 0, 0, 1, 1, 1}, dy8[] = {-1, 0, 1, -1, 1, -1, 0, 1};
istream& operator>>(istream& is, i128& val) {
string str;
is >> str;
val = 0;
bool flag = false;
if (str[0] == '-') flag = true, str = str.substr(1);
for (char& c : str) val = val * 10 + c - '0';
if (flag) val = -val;
return is;
}
ostream& operator<<(ostream& os, i128 val) {
if (val < 0) os << "-", val = -val;
if (val > 9) os << val / 10;
os << static_cast<char>(val % 10 + '0');
return os;
}
bool cmp(LD a, LD b) {
if (fabs(a - b) < EPS) return 1;
return 0;
}
struct Hash {
vector<int> h, p;
int B = 131;
Hash(const string& s) {
int n = s.size();
h.resize(n + 1, 0);
p.resize(n + 1, 1);
for (int i = 0; i < n; ++i) {
p[i + 1] = p[i] * B % MOD;
h[i + 1] = (h[i] * B + s[i]) % MOD;
}
}
LL get(int l, int r) {
LL v = h[r] - h[l - 1] * p[r - l + 1] % MOD;
v = (v % MOD + MOD) % MOD;
return v;
}
};
void solve() {
int n;
cin >> n;
vec1(int, a, n, 0);
for (int i = 0; i < n; ++i) cin >> a[i];
if (n == 1) {
cout << "Alice" << '\n';
return;
}
if (a[0] > 1) {
cout << "Alice" << '\n';
return;
}
int idx = -1;
for (int i = 0; i < n; ++i) {
if (a[i] > 1) {
idx = i;
break;
}
}
if (idx == -1) {
if (n & 1) {
cout << "Alice" << '\n';
}
else {
cout << "Bob" << '\n';
}
return;
}
if (idx & 1) {
cout << "Bob" << '\n';
}
else cout << "Alice" << '\n';
/**/ #ifdef LOCAL
cout << flush;
/**/ #endif
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int T;
cin >> T;
while (T--) solve();
cout << fixed << setprecision(15);
return 0;
}

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