Android自學筆記-16-任務棧

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題目連結：http://acm.fzu.edu.cn/problem.php?pid=2170

貼個baka爺的代碼留念。。

資料出的有問題，輸入的字串長度不超過1000

#include<iostream>#include<cstdio>#include<cstring>#include<string>#include<algorithm>#include<map>#include<queue>#include<stack>#include<cmath>#include<vector>#define inf 0x3f3f3f3f#define Inf 0x3FFFFFFFFFFFFFFFLL#define eps 1e-9#define pi acos(-1.0)using namespace std;typedef long long ll;const int maxn=1000+2;const int mod=1000000007;int dp[maxn][maxn];char str[maxn<<1];int main(){    //freopen("in.txt","r",stdin);    //freopen("out.txt","w",stdout);    int t,n;    scanf("%d",&t);    while(t--)    {        scanf("%d",&n);        memset(dp,0,sizeof(dp));        scanf("%s",str+1);        dp[0][0]=1;        int k;        for(int i=0;i<=n;++i)            for(int j=0;j<=n;++j)            {                if(!dp[i][j]) continue;                k=i+j+1;                if((i&1)&&(j&1))                {                    if(str[k]==‘B‘)                    {                        dp[i][j+1]+=dp[i][j];                        dp[i+1][j]+=dp[i][j];                        if(dp[i][j+1]>=mod) dp[i][j+1]-=mod;                        if(dp[i+1][j]>=mod) dp[i+1][j]-=mod;                    }                }                else if(i&1)                {                    if(str[k]==‘W‘)                    {                        dp[i][j+1]+=dp[i][j];                        if(dp[i][j+1]>=mod) dp[i][j+1]-=mod;                    }                    else                    {                        dp[i+1][j]+=dp[i][j];                        if(dp[i+1][j]>=mod) dp[i+1][j]-=mod;                    }                }                else if(j&1)                {                    if(str[k]==‘W‘)                    {                        dp[i+1][j]+=dp[i][j];                        if(dp[i+1][j]>=mod) dp[i+1][j]-=mod;                    }                    else                    {                        dp[i][j+1]+=dp[i][j];                        if(dp[i][j+1]>=mod) dp[i][j+1]-=mod;                    }                }                else                {                    if(str[k]==‘W‘)                    {                        dp[i][j+1]+=dp[i][j];                        dp[i+1][j]+=dp[i][j];                        if(dp[i][j+1]>=mod) dp[i][j+1]-=mod;                        if(dp[i+1][j]>=mod) dp[i+1][j]-=mod;                    }                }            }        int ans=dp[n][n];        printf("%d\n",ans);    }    return 0;}