Submission #68675

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
68675	2018-08-18 01:54:03	IvanC	Tents (JOI18_tents)	C++17	100 / 100	312 ms	71920 KiB

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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 3010;
const int MOD = 1e9 + 7;
ll escolhe2(ll x){
  return (x * (x-1))/2;
}
ll dp[MAXN][MAXN];
int H,W;
ll solve(int a,int b){
  if(a < 0 || b < 0) return 0;
  if(a == 0 || b == 0) return 1;
  if(dp[a][b] != -1) return dp[a][b];
  ll qtd = solve(a-1,b);
  qtd += solve(a - 1,b - 2)*escolhe2(b);
  qtd += 4*solve(a-1,b-1)*b;
  qtd += solve(a - 2,b - 1)*b*(a-1);
  if(a == H && b == W) qtd--;
  qtd %= MOD;
  return dp[a][b] = qtd;
 
 
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• Subtask 1: 48 / 48
• Subtask 2: 52 / 52