2016-2017 ACM-ICPC Southeastern European Regional Programming Contest (SEERC 2016)

A - Concerts

思路：dp[i][j]表示前i天看了j场演唱会。转移方程：dp[i][j]=dp[i-1][j]+dp[由h数组决定的前一场的最晚日期][j-1]。

#include<bits/stdc++.h>
using namespace std;
int h[300];
char plan[305],schedule[100005];
int k,n;
int dp[100005][305];
const int mod=1e9+7;
int main()
{
    while(~scanf("%d%d",&k,&n))
    {
        for(int i='A';i<='Z';++i)scanf("%d",h+i);
        scanf("%s%s",plan,schedule);
        dp[1][1]=(plan[0]==schedule[0]);for(int i=2;i<=n;++i)dp[i][1]=(plan[0]==schedule[i-1])?dp[i-1][1]+1:dp[i-1][1];
        for(int i=2;i<=k;++i)dp[1][i]=0;
        for(int j=2;j<=k;++j)
        {
            for(int i=2;i<=n;++i)
            {
                dp[i][j]=dp[i-1][j];
                if(plan[j-1]==schedule[i-1]&&i-h[plan[j-2]]>=2)dp[i][j]=(1LL*dp[i][j]+dp[i-1-h[plan[j-2]]][j-1])%mod;
            }
        }
        printf("%d
",dp[n][k]);
    }
}

D - Harry Potter and The Vector Spell

思路：并查集

#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+5;
vector<int> a[maxn];
int n,m;
int fa[maxn];
int find(int x){return x==fa[x]?x:fa[x]=find(fa[x]);}
int main()
{
    while(~scanf("%d%d",&m,&n))
    {
        for(int i=1;i<=m;++i)
        {
            fa[i]=i;
            int k,tmp;scanf("%d",&k);
            for(int j=1;j<=k;++j)
            {
                scanf("%d",&tmp);
                a[tmp].push_back(i);
            }
        }
        int ans=0;
        for(int i=1;i<=n;++i)
        {
            int u=a[i][0],v=a[i][1];
            int x=find(u),y=find(v);
            if(x!=y){ans++;fa[x]=y;}
        }
        printf("%d
",ans);
    }
}

G - Robots

水题

K - Escape room

水题