#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
using namespace std;
typedef long long ll;
typedef __int128 lll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pld;
#define MAX 9223372036854775807LL
#define MIN -9223372036854775807LL
#define INF 0x3f3f3f3f3f3f3f3f
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << fixed; cout.precision(10);
#define sp << " "
#define en << "\n"
#define compress(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(), v.end()), v.end())
inline int readChar();
template<class T = int> inline T readInt();
template<class T> inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);
static const int buf_size = 1 << 18;
inline int getChar(){
#ifndef LOCAL
static char buf[buf_size];
static int len = 0, pos = 0;
if(pos == len) pos = 0, len = fread(buf, 1, buf_size, stdin);
if(pos == len) return -1;
return buf[pos++];
#endif
}
inline int readChar(){
#ifndef LOCAL
int c = getChar();
while(c <= 32) c = getChar();
return c;
#else
char c; cin >> c; return c;
#endif
}
template <class T>
inline T readInt(){
#ifndef LOCAL
int s = 1, c = readChar();
T x = 0;
if(c == '-') s = -1, c = getChar();
while('0' <= c && c <= '9') x = x * 10 + c - '0', c = getChar();
return s == 1 ? x : -x;
#else
T x; cin >> x; return x;
#endif
}
static int write_pos = 0;
static char write_buf[buf_size];
inline void writeChar(int x){
if(write_pos == buf_size) fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
write_buf[write_pos++] = x;
}
template <class T>
inline void writeInt(T x, char end){
if(x < 0) writeChar('-'), x = -x;
char s[24]; int n = 0;
while(x || !n) s[n++] = '0' + x % 10, x /= 10;
while(n--) writeChar(s[n]);
if(end) writeChar(end);
}
inline void writeWord(const char *s){
while(*s) writeChar(*s++);
}
struct Flusher{
~Flusher(){ if(write_pos) fwrite(write_buf, 1, write_pos, stdout), write_pos = 0; }
}flusher;
int n;
pair<int, int> a[1010];
int ss = 1000000007;
int inv[1010];
vector<int> zip;
ll dp[1010][1010];
ll LC[1010];
ll xjc[1010];
int num[1010];
ll fast_mod(ll X)
{
return X >= ss ? X % ss : X;
}
ll sqrmtp(ll X, ll Y)
{
ll ret = 1;
while(Y)
{
if(Y & 1)
ret = fast_mod(ret * X);
X = fast_mod(X * X);
Y >>= 1;
}
return ret;
}
int main(void)
{
fastio
n = readInt();
//cin >> n;
for(int i = 1 ; i <= n ; ++i)
{
a[i].fi = readInt();
a[i].se = readInt();
//cin >> a[i].fi >> a[i].se;
zip.push_back(a[i].fi);
zip.push_back(a[i].se + 1);
}
for(int i = 1 ; i <= n ; ++i)
inv[i] = sqrmtp(i, ss - 2);
compress(zip);
dp[0][0] = 1;
for(int i = 1 ; i <= n ; ++i)
dp[0][i] = 1;
int siz = (ll)zip.size();
for(int i = 1 ; i < siz ; ++i)
{
int siz2 = 0;
for(int j = 1 ; j <= n ; ++j)
{
if(a[j].fi <= zip[i - 1] && zip[i] - 1 <= a[j].se)
num[siz2++] = j;
}
int L = zip[i] - zip[i - 1];
LC[0] = 1;
for(int j = 1 ; j <= siz2 ; ++j)
{
if(L <= 0)
break;
LC[j] = fast_mod(fast_mod(LC[j - 1] * L) * inv[j]);
L--;
}
L = zip[i] - zip[i - 1];
for(int j = 0 ; j <= siz2 - 2 ; ++j)
{
ll gap = j;
ll gap2 = 1;
xjc[j] = 0;
if(L <= 1)
break;
xjc[j] = LC[2];
for(int k = 1 ; ; ++k)
{
if(k + 2 > L || k > j)
break;
gap2 = fast_mod(fast_mod(gap2 * gap) * inv[k]);
--gap;
xjc[j] = fast_mod(xjc[j] + gap2 * LC[k + 2]);
}
}
for(int j = 0 ; j < siz2 ; ++j)
{
dp[i][num[j]] = fast_mod(dp[i][num[j]] + dp[i - 1][num[j] - 1] * LC[1]);
if(L >= 2)
{
for(int k = 0 ; k < j ; ++k)
dp[i][num[j]] = fast_mod(dp[i][num[j]] + dp[i - 1][num[k] - 1] * xjc[j - k - 1]);
}
}
for(int j = 0 ; j <= n ; ++j)
{
dp[i][j] = fast_mod(dp[i][j] + dp[i - 1][j] + dp[i][j - 1]);
if(j)
dp[i][j] = fast_mod(dp[i][j] - dp[i - 1][j - 1]);
}
}
dp[siz - 1][n]--;
dp[siz - 1][n] = (dp[siz - 1][n] + ss) % ss;
cout << dp[siz - 1][n];
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
7 ms |
8276 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
7 ms |
8276 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
5 ms |
1236 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
7 ms |
8276 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |