Submission #559569

#	Time	Username	Problem	Language	Result	Execution time	Memory
559569		Pherokung	Kangaroo (CEOI16_kangaroo)	C++14	100 / 100	26 ms	22940 KiB

kangaroo

#include<bits/stdc++.h>
using namespace std;
#define N 2005
#define ll long long
const int mod = 1e9+7;
int n,cs,cf,d=0;
ll dp[N][N],ans;

int main(){
	scanf("%d%d%d",&n,&cs,&cf);
	
	dp[0][0] = 1;
	for(int idx=1;idx<=n;idx++){
		for(int comp=1;comp<=idx;comp++){
			if(idx == cs || idx == cf){
				dp[idx][comp] += dp[idx-1][comp];
				dp[idx][comp] %= mod;
				
				dp[idx][comp] += dp[idx-1][comp-1];
				dp[idx][comp] %= mod;
			}
			else{
				int v = comp - (idx > cs) - (idx > cf);
				dp[idx][comp] += dp[idx-1][comp-1] * (v);
				dp[idx][comp] %= mod;
				
				dp[idx][comp] += dp[idx-1][comp+1] * (comp);
				dp[idx][comp] %= mod;
			}
		}
	}
	
	printf("%lld",dp[n][1]);
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:10:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |  scanf("%d%d%d",&n,&cs,&cf);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 30 / 30
• Subtask 3: 15 / 15
• Subtask 4: 49 / 49