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https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
37 lines
1009 B
C++
37 lines
1009 B
C++
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#include <iostream>
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#include <cstring>
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#include <cstdio>
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#include <math.h>
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#include <cstdlib>
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#include <queue>
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#include <algorithm>
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using namespace std;
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#define N 1050
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#define mod 100000007
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int dp[N][N*2][2];
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int main ()
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{
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memset(dp,0,sizeof(dp));
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dp[1][1][0]=1;
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dp[1][2][1]=1;
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for(int i=1;i<=1000;++i)
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{
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for(int j=1;j<=2*i;++j)
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{
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dp[i+1][j][0]=(dp[i+1][j][0]+dp[i][j][0]+2*dp[i][j][1])%mod;
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dp[i+1][j+1][0]=(dp[i+1][j+1][0]+dp[i][j][1]+dp[i][j][0])%mod;
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dp[i+1][j][1]=(dp[i+1][j][1]+dp[i][j][1])%mod;
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dp[i+1][j+1][1]=(dp[i+1][j+1][1]+2*dp[i][j][0]+2*dp[i][j][1])%mod;
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dp[i+1][j+2][1]=(dp[i+1][j+2][1]+dp[i][j][0]+dp[i][j][1])%mod;
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}
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}
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int n,k;
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int t;scanf("%d",&t);
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while(t--)
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{
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scanf("%d%d",&n,&k);
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printf("%d\n",(dp[n][k][0]+dp[n][k][1])%mod);
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}
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return 0;
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}
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