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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#449378 | #8526. Polygon II | ucup-team3734 | RE | 1ms | 3636kb | C++23 | 3.7kb | 2024-06-21 05:44:06 | 2024-06-21 05:44:06 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long i64;
typedef unsigned long long u64;
typedef double lf;
const int mod = 1'000'000'000 + 7;
template<typename T>
T add(T x) {
return x;
}
template<typename T, typename... Ts>
T add(T x, Ts... y) {
T res = x + add(y...);
if (res >= mod)
res -= mod;
return res;
}
template<typename T, typename... Ts>
T sub(T x, Ts... y) {
return add(x, mod - add(y...));
}
template<typename T, typename... Ts>
void udd(T &x, Ts... y) {
x = add(x, y...);
}
template<typename T>
T mul(T x) {
return x;
}
template<typename T, typename... Ts>
T mul(T x, Ts... y) {
return (x * 1ll * mul(y...)) % mod;
}
template<typename T, typename... Ts>
void uul(T &x, Ts... y) {
x = mul(x, y...);
}
int bin(int a, i64 deg) {
int r = 1;
while (deg) {
if (deg & 1)
uul(r, a);
deg >>= 1;
uul(a, a);
}
return r;
}
int inv(int x) {
assert(x);
return bin(x, mod - 2);
}
const int maxb = 55;
void solve() {
int n;
cin >> n;
vector<int> cnt(maxb + 1);
vector<int> cnt_bit(maxb + 1);
int maxv = 0;
for (int i = 0; i < n; i++) {
int x;
cin >> x;
cnt[x]++;
maxv = max(maxv, x);
for (int j = 0; j < x; ++j) {
cnt_bit[j]++;
}
}
int half = inv(2);
vector<int> pows(maxb * n + 1);
pows[0] = 1;
for (int i = 1; i <= maxb * n; ++i) {
pows[i] = mul(pows[i - 1], half);
}
vector< vector<int> > choose(maxb + 1, vector<int>(maxb + 1));
choose[0][0] = 1;
for (int i = 1; i <= maxb; ++i) {
choose[i][0] = 1;
for (int j = 1; j <= i; ++j) {
choose[i][j] = add(choose[i - 1][j], choose[i - 1][j - 1]);
}
}
vector<int> cdf(n + 1);
int inv_fact = 1;
for (int i = 0; i < n; ++i) {
uul(inv_fact, inv(i + 1));
}
for (int i = 0; i <= n; ++i) {
int sgn = 1;
for (int k = 0; k <= i; ++k) {
udd(cdf[i], mul(sgn, choose[n][k], bin(sub(i, k), n)));
sgn = sub(0, sgn);
}
uul(cdf[i], inv_fact);
}
vector< vector<int> > dp(maxv + 1, vector<int>(2 * n + 1));
for (int i = 0; i < n; ++i) {
dp[0][i] = sub(cdf[i + 1], cdf[i]);
}
for (int i = 1; i <= maxv; ++i) {
for (int j = 0; j <= 2 * n; ++j) {
int &res = dp[i][j];
for (int k = 0; k <= cnt_bit[i - 1]; ++k) {
int v = 0;
if (0 <= 2 * j - k && 2 * j - k <= 2 * n) {
udd(v, dp[i - 1][2 * j - k]);
}
if (0 <= 2 * j - k + 1 && 2 * j - k + 1 <= 2 * n) {
udd(v, dp[i - 1][2 * j - k + 1]);
}
uul(v, choose[cnt_bit[i - 1]][k], pows[cnt_bit[i - 1]]);
udd(res, v);
}
}
}
vector<int> prob_ge(maxv + 1);
for (int i = 0; i <= maxv; ++i) {
int high = 0;
for (int j = i; j <= maxv; ++j) {
high += cnt_bit[j];
}
prob_ge[i] = sub(1, pows[high]);
int v = 0;
for (int j = 1; j <= 2 * n; ++j) {
udd(v, dp[i][j]);
}
udd(prob_ge[i], mul(v, pows[high]));
}
int ans = 0;
for (int i = 0; i <= maxv; ++i) {
udd(ans, mul(cnt[i], sub(1, prob_ge[i])));
}
cout << sub(1, ans) << '\n';
}
signed main() {
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
#endif
ios_base::sync_with_stdio(false);
int t = 1;
// cin >> t;
for (int i = 0; i < t; i++) {
solve();
}
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 3560kb
input:
3 0 2 0
output:
166666668
result:
ok 1 number(s): "166666668"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3600kb
input:
3 0 0 0
output:
500000004
result:
ok 1 number(s): "500000004"
Test #3:
score: 0
Accepted
time: 1ms
memory: 3536kb
input:
3 5 6 7
output:
208333335
result:
ok 1 number(s): "208333335"
Test #4:
score: 0
Accepted
time: 0ms
memory: 3532kb
input:
3 0 25 50
output:
889268532
result:
ok 1 number(s): "889268532"
Test #5:
score: 0
Accepted
time: 1ms
memory: 3636kb
input:
10 39 11 25 1 12 44 10 46 27 15
output:
913863330
result:
ok 1 number(s): "913863330"
Test #6:
score: -100
Runtime Error
input:
57 43 22 3 16 7 5 24 32 25 16 41 28 24 30 28 10 32 48 41 43 34 37 48 34 3 9 21 41 49 25 2 0 36 45 34 33 45 9 42 29 43 9 38 34 44 33 44 6 46 39 22 36 40 37 19 34 3