#include <bits/stdc++.h>
#define int long long
using namespace std;
const int mod=1e9+7;
int dp[1005][505], inv[505], a[505], b[505], c[1005];
set<int> s;
int f(int x, int y) {
if (!y) return 1;
int res=f(x, y/2);
if (y&1) return res*res%mod*x%mod;
else return res*res%mod;
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
int n, m=0;
cin >> n;
for (int i=1; i<=n; i++) inv[i]=f(i, mod-2);
for (int i=1; i<=n; i++) {
cin >> a[i] >> b[i];
s.insert(a[i]);
s.insert(b[i]+1);
}
for (auto itr=s.begin(); itr!=s.end(); itr++) [++m]=(*itr);
for (int i=0; i<=n; i++) dp[0][i]=1;
for (int i=1; i<m; i++) {
for (int j=0; j<=n; j++) {
dp[i][j]=dp[i-1][j];
int num=1, cnt=0;
for (int k=1; k<=j; k++) {
if (a[j-k+1]<=c[i] && c[i+1]-1<=b[j-k+1]) {
cnt++;
num=num*(c[i+1]-c[i]+cnt-1)%mod*inv[cnt]%mod;
dp[i][j]=(dp[i][j]+dp[i-1][j-k]*num)%mod;
}
}
}
}
cout << dp[m-1][n]-1;
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:25:52: error: expected identifier before '++' token
25 | for (auto itr=s.begin(); itr!=s.end(); itr++) [++m]=(*itr);
| ^~
boat.cpp: In lambda function:
boat.cpp:25:56: error: expected '{' before '=' token
25 | for (auto itr=s.begin(); itr!=s.end(); itr++) [++m]=(*itr);
| ^
boat.cpp: In function 'int main()':
boat.cpp:25:62: error: no match for 'operator=' (operand types are 'main()::<lambda()>' and 'const long long int')
25 | for (auto itr=s.begin(); itr!=s.end(); itr++) [++m]=(*itr);
| ^
boat.cpp:25:55: note: candidate: 'main()::<lambda()>& main()::<lambda()>::operator=(const main()::<lambda()>&)' (deleted)
25 | for (auto itr=s.begin(); itr!=s.end(); itr++) [++m]=(*itr);
| ^
boat.cpp:25:55: note: no known conversion for argument 1 from 'const long long int' to 'const main()::<lambda()>&'
