Codeforces 931 概率DP

A

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
const int maxn = ;
int main()
{
        int n, m;
        while (cin >> n >> m)
        {
                int mid = (n + m) / ;
                //cout<<mid<<endl;
                int x1 = abs(mid - n);
                int x2 = abs(m - mid);
                int ans = ( + x1) * x1 /  + ( + x2) * x2 / ;
                cout << ans << endl;
        }

}

B

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll Mod = ;
int main()
{
        int n;
        cin >> n;
        int a, b;
        cin >> a >> b;
        if (a > b)
        {
                swap(a, b);
        }
        if (a <= n /  && b > n / )
        {
                cout << "Final!" << endl;
                return ;
        }
        int anser = ;
        while (true)
        {
                a = (a + (a % )) / ;
                b = (b + (b % )) / ;
                if (a == b)
                {
                        cout << anser << endl;
                        return ;
                }
                anser++;
        }
        return ;
}

C

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
const int maxn = ;
int num[];
int anser;
int main()
{
    int mx=-;
    int mn=;
    int mxnum=;
    int mnnum=;
    int n;
    cin >> n;
    anser=n;
    for(int i=; i<=n; i++)
    {
        scanf("%d",&num[i]);
        mx=max(mx,num[i]);
        mn=min(mn,num[i]);
    }
    if(mx-mn<=)
    {
        cout<<n<<endl;
        for(int i=; i<=n; i++)
            cout<<num[i]<<" ";
            cout<<endl;
        return ;
    }
    for(int i=; i<=n; i++)
    {
        if(num[i]==mx)
            mxnum++;
        else if(num[i]==mn)
            mnnum++;
    }
    int midnum=n-mxnum-mnnum;
    if(midnum/>=min(mxnum,mnnum))
    {
        int cur=midnum/;
        int cur1=cur;
        for(int i=; i<=n; i++)
        {
            if(num[i]==mn+&&cur)
            {
                anser--;
                num[i]--;
                cur--;
                continue;
            }
            if(num[i]==mn+&&cur1)
            {
                anser--;
                num[i]++;
                cur1--;
                continue;
            }
        }
    }
    else
    {
        int cur=min(mxnum,mnnum);
        int cur1=cur;
        for(int i=;i<=n;i++)
        {
          if(num[i]==mn&&cur)
          {
              num[i]++;
              anser--;
              cur--;
              continue;
          }
          if(num[i]==mx&&cur1)
          {
              num[i]--;
              anser--;
              cur1--;
              continue;
          }
        }
    }
    cout<<anser<<endl;
    for(int i=;i<=n;i++)
        cout<<num[i]<<" ";
    cout<<endl;

}

D

思维题 一层一层地消

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
const int maxn = ;
int nextt[];
int num[];
int level[];
int dp[];
int anser = ;
int main()
{
        int n;
        cin >> n;
        dp[] = level[] = dp[] = ;
        for (int i = ; i <= n; i++)
        {
                scanf("%d", &nextt[i]);
                dp[i] = dp[nextt[i]] + ;
                level[dp[i]]++;
        }
        for(int i=;i<=;i++)
        {
                if(level[i]&)
                anser++;
        }
        cout<<anser<<endl;
        return ;
}

E

状压DP

dp[i][j][k]表示第一个字母是i第二个字母是j距离为k有多少个

因为第一个字母是由第一个玩家定的 所以无法选择 第二个字母可以选择但只能最优地选一次 所以ans+=now 取所有长度里面概率最高的

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxn = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
const int turn2[][] = {{, }, { -, }, {, }, {, -}, {, -}, { -, -}, {, }, { -, }};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
char a[];
int dp[][][];
int anser = ;
int main()
{
        scanf("%s", a + );
        int len = strlen(a + );
        for (int i = ; i <= len; i++)
        {
                a[i + len] = a[i];
        }
        for (int i = ; i <= len; i++)
        {
                for (int j = i + ; j < i + len; j++)
                {
                        dp[a[i] - 'a'][a[j] - 'a'][j - i + ]++;
                }
        }
        int now = ;
        int cur;
        for (int i = ; i < ; i++)
        {
                now = ;
                for (int j = ; j <= len; j++)
                {
                        cur = ;
                        for (int k = ; k < ; k++)
                        {
                                if (dp[i][k][j] == )
                                {
                                        cur++;
                                }
                        }
                        now = max(now, cur);
                }
                anser += now;
        }
        printf("%.10f", (double)anser / len);
        return ;
}

F

待补