oj.uz

Submission #494893

# Submission time Handle Problem Language Result Execution time Memory
494893 2021-12-17T09:59:46 Z jamezzz Boat (APIO16_boat) C++17
9 / 100
 746 ms 8004 KB 
#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));

#define mod 1000000007

inline int add(int a,int b){
	int r=a+b;
	while(r>=mod)r-=mod;
	while(r<0)r+=mod;
	return r;
}

inline int mult(int a,int b){
	return (int)(((ll)a*b)%mod);
}

inline int rd(){
    int x=0;
    char ch=getchar_unlocked();
    while(ch<'0'||ch>'9')ch=getchar_unlocked();
    while(ch>='0'&&ch<='9'){
		x=(x<<3)+(x<<1)+ch-'0';
		ch=getchar_unlocked();
	}
    return x;
}

int n,m,a[505],b[505],memo[505][1005],c[1005][505],c2[505][505],w[1005][505],inv[505];
vector<int> v[1005],d;

int fp(int a,int x){
	if(x==0)return 1;
	int t=fp(a,x/2);
	int r=mult(t,t);
	if(x%2)r=mult(r,a);
	return r;
}

int choose(int a,int b){
	int r=1;
	for(int i=a-b+1;i<=a;++i)r=mult(r,i);
	for(int i=1;i<=b;++i)r=mult(r,inv[i]);
	return r;
}

int dp(int i,int j){//covered up to the ith segment,now deciding for jth segment
	if(i==n)return 1;
	if(j==m)return (i!=0);
	if(memo[i][j]!=-1)return memo[i][j];
	int s=upper_bound(all(v[j]),i)-v[j].begin();
	int ans=dp(i,j+1);
	for(int t=s;t<sz(v[j]);++t){
		ans=add(ans,mult(w[j][t-s+1],dp(v[j][t],j+1)));
	}
	return memo[i][j]=ans;
}

int main(){
	sf("%d",&n);
	for(int i=1;i<=n;++i){
		sf("%d%d",&a[i],&b[i]);
		d.pb(a[i]);d.pb(b[i]+1);
	}
	disc(d);m=sz(d);d.pb(d.back()+1);
	for(int i=1;i<=n;++i){
		for(int j=0;j<m;++j){
			if(a[i]<=d[j]&&d[j]<=b[i])v[j].pb(i);
		}
	}
	for(int i=1;i<=n;++i)inv[i]=fp(i,mod-2);
	for(int i=0;i<m;++i){
		int a=d[i+1]-d[i];
		for(int b=1;b<=sz(v[i]);++b){
			c[i][b]=choose(a,b);
		}
	}
	for(int i=1;i<=n;++i){
		for(int j=0;j<=i;++j){
			c2[i][j]=choose(i,j);
		}
	}
	for(int i=0;i<m;++i){
		int a=d[i+1]-d[i];
		for(int b=1;b<=sz(v[i]);++b){
			for(int k=0;k<b;++k){
				w[i][b]=add(w[i][b],mult(c[i][k+1],c2[b][k]));
			}
		}
	}
	memset(memo,-1,sizeof memo);
	pf("%d\n",dp(0,0));
}

/*
2
1 2
2 3
*/

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:112:7: warning: unused variable 'a' [-Wunused-variable]
  112 |   int a=d[i+1]-d[i];
      |       ^
boat.cpp:88:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |  sf("%d",&n);
      |    ^
boat.cpp:90:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |   sf("%d%d",&a[i],&b[i]);
      |     ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 215 ms 7292 KB Output is correct
2 Correct 212 ms 7324 KB Output is correct
3 Correct 213 ms 7264 KB Output is correct
4 Correct 210 ms 7344 KB Output is correct
5 Correct 214 ms 7236 KB Output is correct
6 Correct 219 ms 7512 KB Output is correct
7 Correct 216 ms 7300 KB Output is correct
8 Correct 217 ms 7328 KB Output is correct
9 Correct 224 ms 7432 KB Output is correct
10 Correct 215 ms 7292 KB Output is correct
11 Correct 220 ms 7320 KB Output is correct
12 Correct 214 ms 7340 KB Output is correct
13 Correct 215 ms 7280 KB Output is correct
14 Correct 213 ms 7336 KB Output is correct
15 Correct 213 ms 7236 KB Output is correct
16 Correct 207 ms 4132 KB Output is correct
17 Correct 208 ms 4000 KB Output is correct
18 Correct 207 ms 3960 KB Output is correct
19 Correct 208 ms 4136 KB Output is correct
20 Correct 205 ms 4040 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 215 ms 7292 KB Output is correct
2 Correct 212 ms 7324 KB Output is correct
3 Correct 213 ms 7264 KB Output is correct
4 Correct 210 ms 7344 KB Output is correct
5 Correct 214 ms 7236 KB Output is correct
6 Correct 219 ms 7512 KB Output is correct
7 Correct 216 ms 7300 KB Output is correct
8 Correct 217 ms 7328 KB Output is correct
9 Correct 224 ms 7432 KB Output is correct
10 Correct 215 ms 7292 KB Output is correct
11 Correct 220 ms 7320 KB Output is correct
12 Correct 214 ms 7340 KB Output is correct
13 Correct 215 ms 7280 KB Output is correct
14 Correct 213 ms 7336 KB Output is correct
15 Correct 213 ms 7236 KB Output is correct
16 Correct 207 ms 4132 KB Output is correct
17 Correct 208 ms 4000 KB Output is correct
18 Correct 207 ms 3960 KB Output is correct
19 Correct 208 ms 4136 KB Output is correct
20 Correct 205 ms 4040 KB Output is correct
21 Incorrect 746 ms 8004 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 8 ms 3276 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 215 ms 7292 KB Output is correct
2 Correct 212 ms 7324 KB Output is correct
3 Correct 213 ms 7264 KB Output is correct
4 Correct 210 ms 7344 KB Output is correct
5 Correct 214 ms 7236 KB Output is correct
6 Correct 219 ms 7512 KB Output is correct
7 Correct 216 ms 7300 KB Output is correct
8 Correct 217 ms 7328 KB Output is correct
9 Correct 224 ms 7432 KB Output is correct
10 Correct 215 ms 7292 KB Output is correct
11 Correct 220 ms 7320 KB Output is correct
12 Correct 214 ms 7340 KB Output is correct
13 Correct 215 ms 7280 KB Output is correct
14 Correct 213 ms 7336 KB Output is correct
15 Correct 213 ms 7236 KB Output is correct
16 Correct 207 ms 4132 KB Output is correct
17 Correct 208 ms 4000 KB Output is correct
18 Correct 207 ms 3960 KB Output is correct
19 Correct 208 ms 4136 KB Output is correct
20 Correct 205 ms 4040 KB Output is correct
21 Incorrect 746 ms 8004 KB Output isn't correct
22 Halted 0 ms 0 KB -