Codeforces 932 数组环构造 树上LCA倍增

A

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!
")
#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-8;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 3e7 + 10;
const int  maxm = 300;
const int turn[4][2] = {{1, 0}, { -1, 0}, {0, 1}, {0, -1}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 1e9 + 7;
int main()
{
        string a;
        cin >> a;
        string ans;
        ans = a;
        for (int i = 1; i <= a.size(); i++)
        {
                ans += a[a.size() - i];
        }
        cout << ans << endl;
        return 0;
}

B

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!
")
#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-8;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 3e7 + 10;
const int  maxm = 300;
const int turn[4][2] = {{1, 0}, { -1, 0}, {0, 1}, {0, -1}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
int ans[1000005][10];
ll mod = 1e9 + 7;
int getans(int x)
{
        if (x < 10)
        {
                return x;
        }
        else
        {
                int cur = 1;
                while (x > 0)
                {
                        if (x % 10 != 0)
                        {
                                cur *= x % 10;
                        }
                        x /= 10;
                }
                return getans(cur);
        }
}
int main()
{
        for (int i = 1; i <= 1000001; i++)
        {
                int now = getans(i);
                for (int j = 1; j <= 9; j++)
                {
                        ans[i][j] = ans[i - 1][j];
                }
                ans[i][now]++;
        }
        int q;
        cin >> q;
        int l, r, k;
        for (int i = 1; i <= q; i++)
        {
                scanf("%d %d %d", &l, &r, &k);
                cout << ans[r][k] - ans[l - 1][k] << endl;
        }
        return 0;
}

C

构造题  要求构造出一个数列满足下列条件 

可以看成构造有向图里面的环

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!
")
#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-8;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 3e7 + 10;
const int  maxm = 300;
const int turn[4][2] = {{1, 0}, { -1, 0}, {0, 1}, {0, -1}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
int ans[1000005][10];
ll mod = 1e9 + 7;
int main()
{
        int n, a, b;
        cin >> n >> a >> b;
        int x, y;
        x = y = -1;
        int cnt = n / a;
        for (int i = 0; i <= cnt; i++)
        {
                if ((n - i * a) % b == 0)
                {
                        x = i;
                        y = (n - i * a) / b;
                        break;
                }
        }
        if (x == -1)
        {
                cout << -1 << endl;
                return 0;
        }
        int cur = 0;
        for (int i = 1; i <= x; i++)
        {
                cout << cur + a << " ";
                for (int j = 1; j <= a - 1; j++)
                {
                        cout << cur + j << " ";
                }
                cur += a;
        }
        for (int i = 1; i <= y; i++)
        {
                cout << cur + b << " ";
                for (int j = 1; j <= b - 1; j++)
                {
                        cout << cur + j << " ";
                }
                cur += b;
        }
        //cout << endl;
        return 0;
}

D

https://www.cnblogs.com/AWCXV/p/8453152.html

https://www.cnblogs.com/forever97/p/cf463.html

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!
")
#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[4][2] = {{1, 0}, { -1, 0}, {0, 1}, {0, -1}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
const int N = 4e5;
const int M = 20;
const ll INF = 1e16;
int Q;
ll last, W[N + 10], sum[N + 10][M + 10];
int f[N + 10][M + 10], cnt = 1;
int main()
{
        cin >> Q;
        for (int i = 0; i <= 20; i++)
        {
                sum[1][i] = sum[0][i] = INF;
        }
        W[0] = INF;
        for(int i=1;i<=Q;i++)
        {
                ll ope, p, q;
                cin >> ope >> p >> q;
                if (ope == 1)
                {
                        ll R = p ^ last, w = q ^ last;
                        cnt++;
                        W[cnt] = w;
                        if (W[R] >= w)
                        {
                                f[cnt][0] = R;
                        }
                        else
                        {
                                ll now = R;
                                for (int i = 20; i >= 0; i--)
                                        if (W[f[now][i]] < w)
                                        {
                                                now = f[now][i];
                                        }
                                f[cnt][0] = f[now][0];
                        }
                        for (int i = 1; i <= 20; i++)
                        {
                                f[cnt][i] = f[f[cnt][i - 1]][i - 1];
                        }

                        sum[cnt][0] = W[f[cnt][0]];

                        for (int i = 1; i <= 20; i++)
                        {
                                if (f[cnt][i] == 0)
                                {
                                        sum[cnt][i] = INF;
                                }
                                else
                                {
                                        sum[cnt][i] = sum[cnt][i - 1] + sum[f[cnt][i - 1]][i - 1];
                                }
                        }
                }
                else
                {
                        ll R = p ^ last, X = q ^ last;
                        int len = 0;
                        if (X < W[R])
                        {
                                cout << 0 << endl;
                                last = 0;
                                continue;
                        }
                        X -= W[R];
                        len++;
                        for (int i = 20; i >= 0; i--)
                        {
                                if (X >= sum[R][i])
                                {
                                        X -= sum[R][i];
                                        R = f[R][i];
                                        len += (1 << i);
                                }
                        }
                        cout << len << endl;
                        last = len;
                }
        }
        return 0;
}