Submission #414104

#	Time	Username	Problem	Language	Result	Execution time	Memory
414104		jamezzz	Asceticism (JOI18_asceticism)	C++14	49 / 100	108 ms	143976 KiB

asceticism

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#include <ext/rope>
using namespace __gnu_cxx;

typedef tree<long long, null_type, less<long long>,
rb_tree_tag, tree_order_statistics_node_update> pbds;
//less_equal for identical elements

//#define DEBUG

#ifdef DEBUG
#define debug(...) printf(__VA_ARGS__);
#else
#define debug(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb emplace_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()
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<int, int> ii;
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;

#define mod 1000000007
int n,k;
ll m[3005][3005];

ll dp(int i,int s){//u want to add i, have s things alrdy
	if(i==n+1&&s==k)return 1;
	if(i>n)return 0;
	if(m[i][s]!=-1)return m[i][s];
	ll res=dp(i+1,s+1)*(i-s) //start a new chain
			+dp(i+1,s)*s; //add to the end of the chain
	res%=mod;
	return m[i][s]=res;
}

int main(){
	sf("%d%d",&n,&k);
	memset(m,-1,sizeof m);
	pf("%lld\n",dp(1,0));
}

Compilation message (stderr)

asceticism.cpp: In function 'int main()':
asceticism.cpp:56:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |  sf("%d%d",&n,&k);
      |    ^

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 51