Submission #572768

#	Time	Username	Problem	Language	Result	Execution time	Memory
572768		79brue	Kangaroo (CEOI16_kangaroo)	C++17	6 / 100	1 ms	468 KiB

kangaroo

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const ll MOD = 1000000007;

int n;
int s, e;
ll DP[2002][2002];

inline void add(int i, int j, int ti, int tj, ll multiplier){
    if(ti<0 || tj<0) return;
    DP[i][j] = (DP[i][j] + DP[ti][tj] * multiplier) % MOD;
}

int main(){
    scanf("%d %d %d", &n, &s, &e);
    DP[0][0] = 1;
    for(int i=1; i<=n; i++){
        for(int j=1; j<=n; j++){
            if(i==s || i==e){
                add(i, j, i-1, j, 1);
                add(i, j, i-1, j-1, 1);
            }
            else{
                add(i, j, i-1, j+1, j);
                add(i, j, i-1, j-1, j-(i<s?0:i<e?1:2));
            }
        }
    }
    printf("%lld", DP[n][1]);
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:18:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     scanf("%d %d %d", &n, &s, &e);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49