Codeforces_825

A.连续1的个数，0用来分割，注意连续的0。

#include<bits/stdc++.h>
using namespace std;

int n;
string s;

int main()
{
    ios::sync_with_stdio();
    cin >> n >> s;
    int now = ,flag = ;
    for(int i = ;i < n;i++)
    {
        if(s[i] == '') now++,flag = ;
        else
        {
            cout << now;
            now = ;
            flag = ;
        }
    }
    if(now || flag) cout << now;
    cout << endl;
    return ;
}

---

B.暴力每个点放X，判断即可。

#include<bits/stdc++.h>
using namespace std;

string s[];

bool ok()
{
    for(int i = ;i <= ;i++)
    {
        for(int j = ;j <= ;j++)
        {
            if(i <= )
            {
                int flag = ;
                for(int ii = i;ii < i+;ii++)
                {
                    if(s[ii][j] != 'X') flag = ;
                }
                if(flag)    return ;
            }
            if(j <= )
            {
                int flag = ;
                for(int jj = j;jj < j+;jj++)
                {
                    if(s[i][jj] != 'X') flag = ;
                }
                if(flag)    return ;
            }
            if(i <=  && j <= )
            {
                int flag = ;
                for(int ii = i,jj = j;ii < i+;ii++,jj++)
                {
                    if(s[ii][jj] != 'X')    flag = ;
                }
                if(flag)    return ;
            }
            if(i >=  && j <= )
            {
                int flag = ;
                for(int ii = i,jj = j;ii > i-;ii--,jj++)
                {
                    if(s[ii][jj] != 'X')   flag = ;
                }
                if(flag)    return ;
            }
        }
    }
    return ;
}
int main()
{
    ios::sync_with_stdio();
    for(int i = ;i <= ;i++)
    {
        cin >> s[i];
        s[i] = ' '+s[i];
    }
    for(int i = ;i <= ;i++)
    {
        for(int j = ;j <= ;j++)
        {
            if(s[i][j] != '.') continue;
            s[i][j] = 'X';
            if(ok())
            {
                cout << "YES" << endl;
                return ;
            }
            s[i][j] = '.';
        }
    }
    cout << "NO" << endl;
    return ;
}

---

C.排序后模拟。

#include<bits/stdc++.h>
using namespace std;

int n,k,a[];

int main()
{
    ios::sync_with_stdio();
    cin >> n >> k;
    for(int i = ;i <= n;i++)   cin >> a[i];
    sort(a+,a++n);
    int ans = ;
    for(int i = ;i <= n;i++)
    {
        while(k* < a[i])
        {
            k *= ;
            ans++;
        }
        k = max(k,a[i]);
    }
    cout << ans << endl;
    return ;
}

---

D.模拟，给字母少的先分配。

#include<bits/stdc++.h>
using namespace std;

string s1,s2;
map<char,int> mp;

int main()
{
    ios::sync_with_stdio();
    cin >> s1 >> s2;
    for(int i = ;i < s1.length();i++)  mp[s1[i]]++;
    int now = ;
    for(int i = ;i < s1.length();i++)
    {
        if(s1[i] != '?')    continue;
        now = (now+)%s2.length();
        if(mp[s2[now]])
        {
            mp[s2[now]]--;
            i--;
        }
        else    s1[i] = s2[now];
    }
    cout << s1 << endl;
    return ;
}

---

E.优先队列逆向拓扑排序。

#include<bits/stdc++.h>
using namespace std;

int n,m,in[] = {},ans[];
vector<int> v[];

int main()
{
    ios::sync_with_stdio();
    cin >> n >> m;
    while(m--)
    {
        int x,y;
        cin >> x >> y;
        v[y].push_back(x);
        in[x]++;
    }
    priority_queue<int> q;
    for(int i = ;i <= n;i++)
    {
        if(!in[i])  q.push(i);
    }
    int cnt = n;
    while(!q.empty())
    {
        int now = q.top();
        q.pop();
        ans[now] = cnt--;
        for(int i = ;i < v[now].size();i++)
        {
            int t = v[now][i];
            if(--in[t] == )    q.push(t);
        }
    }
    for(int i = ;i <= n;i++)   cout << ans[i] << " ";
    cout << endl;
    return ;
}

---

F.预处理最长公共前缀，dp枚举最小串。

#include<bits/stdc++.h>
using namespace std;

string s;
int lcp[][] = {},dp[],cnt[];

int main()
{
    ios::sync_with_stdio();
    cin >> s;
    int n = s.length();
    memset(dp,0x3f,sizeof(dp));
    for(int i = ;i <= ;i++)   cnt[i] = ;
    for(int i = ;i <= ;i++) cnt[i] = ;
    for(int i = ;i <= ;i++)   cnt[i] = ;
    for(int i = ;i <= ;i++) cnt[i] = ;
    for(int i = n-;i >= ;i--)
    {
        for(int j = n-;j >= i;j--)
        {
            if(s[i] == s[j])    lcp[i][j] = lcp[i+][j+]+;
            else    lcp[i][j] = ;
        }
    }
    dp[] = ;
    for(int i = ;i < n;i++)
    {
        for(int j = ;i+j <= n;j++)
        {
            for(int k = i+j,t = ;k <= n;k += j,t++)
            {
                if(lcp[i][k-j] < j)  break;
                dp[k] = min(dp[k],dp[i]+j+cnt[t]);
            }
        }
    }
    cout << dp[n] << endl;
    return ;
}

---

G.记录一个最小的点即可。

#include<bits/stdc++.h>
using namespace std;

int n,q,ans[];
vector<int> v[];

int dfs(int now,int pre)
{
    for(int i = ;i < v[now].size();i++)
    {
        int t = v[now][i];
        if(t == pre)    continue;
        ans[t] = min(t,ans[now]);
        dfs(t,now);
    }
}

int main()
{
    ios::sync_with_stdio();
    cin >> n >> q;
    int x,y;
    for(int i = ;i < n;i++)
    {
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int lastt = ;
    cin >> x >> y;
    y = (lastt+y)%n+;
    ans[y] = y;
    dfs(y,-);
    int minn = y;
    while(--q)
    {
        int x,y;
        cin >> x >> y;
        y = (y+lastt)%n+;
        if(x == )  minn = min(minn,ans[y]);
        else
        {
            lastt = min(ans[y],minn);
            cout << lastt << endl;
        }
    }
    return ;
}