[Codeforces]Codeforces Round #490 (Div. 3)

Posted 2020-11-20 dramstadt

Mishka and Contest

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

int a[200];

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n, k;
    cin >> n >> k;
    for (int i = 0; i < n; i++) cin >> a[i];
    int l = n, r = -1;
    for (int i = 0; i < n; i++) {
        if (a[i] > k) {
            l = i;
            break;
        }
    }
    for (int i = n - 1; i >= 0; i--) {
        if (a[i] > k) {
            r = i;
            break;
        }
    }
    if (l > r) cout << n << endl;
    else cout << (n - (r - l + 1)) << endl;
    return 0;
}

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Reversing Encryption

splay树，模拟也可以

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

class SplayNode {
public:
    SplayNode *child[2];
    char value;
    int size;
    bool flip;
    SplayNode(char c) : value(c), size(1), flip(false) {
        child[0] = child[1] = NULL;
    }
    int getPosition()const {
        return child[0] ? child[0]->size + 1 : 1;
    }
    void maintain() {
        size = 1;
        if (child[0]) {
            size += child[0]->size;
        }
        if (child[1]) {
            size += child[1]->size;
        }
    }
    void pushDown() {
        if (flip) {
            swap(child[0], child[1]);
            for (int i = 0; i < 2; i++) {
                if (child[i]) {
                    child[i]->flip ^= 1;
                }
            }
            flip = false;
        }
    }
};
class SplayTree {
public:
    SplayNode *root;
    void init(char *a, int n);
    void build(SplayNode *&node, char *begin, char *end);
    void rotate(SplayNode *&node, int direction);
    void splay(SplayNode *&node, int position);
    void reverse(int begin, int end);
    void traverse(SplayNode *u);
    void traverse();
};
void SplayTree::init(char *a, int n) {
    build(root, a, a + n - 1);
}
void SplayTree::build(SplayNode *&node, char *begin, char *end) {
    if (begin > end) {
        return;
    }
    char *middle = begin + ((end - begin) >> 1);
    node = new SplayNode(*middle);
    build(node->child[0], begin, middle - 1);
    build(node->child[1], middle + 1, end);
    node->maintain();
}

void SplayTree::rotate(SplayNode *&node, int direction) {
    SplayNode *child = node->child[direction ^ 1];
    node->child[direction ^ 1] = child->child[direction];
    child->child[direction] = node;
    node->maintain();
    child->maintain();
    node = child;
}
void SplayTree::splay(SplayNode *&node, int position) {
    node->pushDown();
    if (node->getPosition() != position) {
        int d = node->getPosition() < position;
        SplayNode *node2 = node->child[d];
        position -= d ? node->getPosition() : 0;
        node2->pushDown();
        if (node2->getPosition() != position) {
            int d2 = node2->getPosition() < position;
            position -= d2 ? node2->getPosition() : 0;
            splay(node2->child[d2], position);
            if (d == d2) {
                rotate(node, d ^ 1);
            } else {
                rotate(node->child[d], d);
            }
        }
        rotate(node, d ^ 1);
    }
}
void SplayTree::reverse(int begin, int end) {
    splay(root, begin);
    splay(root->child[1], end - begin + 2);
    root->child[1]->child[0]->flip ^= 1;
}
void SplayTree::traverse(SplayNode *u) {
    if (!u) {
        return;
    }
    u->pushDown();
    traverse(u->child[0]);
    if (u->value) {
        printf("%c", u->value);
    }
    traverse(u->child[1]);
}
void SplayTree::traverse() {
    traverse(root);
}
SplayTree st;
char a[200];

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    st.init(a, n + 2);
    for (int i = 1; i <= n; i++) {
        if (n % i == 0)
            st.reverse(1, i);
    }
    st.traverse();
    return 0;
}

View Code

Alphabetic Removals

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

string s;
VI v[26], u;
bool f[500000];

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n, k;
    cin >> n >> k;
    cin >> s;
    for (int i = 0; i < n; i++) v[s[i] - ‘a‘].push_back(i);
    for (int i = 0; i < 26; i++) {
        for (int j = 0; j < v[i].size(); j++) {
            u.push_back(v[i][j]);
        }
    }
    memset(f, true, sizeof(f));
    for (int i = 0; i < k; i++) f[u[i]] = false;
    for (int i = 0; i < n; i++) {
        if (f[i]) cout << s[i];
    }
    return 0;
}

View Code

Equalize the Remainders

贪心

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

int cnt[250000], nex[250000];
int n, m, x, r, p, q, t;
VI v;
int getNext(int r) {
    if (cnt[nex[r]] < q) return nex[r];
    else {
        nex[r] = getNext(nex[r]);
        return nex[r];
    }
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    lint ans = 0;
    cin >> n >> m;
    q = n / m;
    memset(cnt, 0, sizeof(cnt));
    for (int i = 0; i < m; i++) nex[i] = i + 1;
    nex[m - 1] = 0;
    for (int i = 0; i < n; i++) {
        cin >> x;
        r = x % m;
        if (cnt[r] < q) p = r;
        else p = getNext(r);
        cnt[p]++;
        ans += (p + m - r) % m;
        v.push_back(x + (p + m - r) % m);
    }
    cout << ans << endl;
    for (int i = 0; i < n; i++) cout << v[i] << ‘ ‘;
    return 0;
}

View Code

Reachability from the Capital

染色，色块数减一

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

VI G[5500];
int color[5500];
bool f[5500];

void dfs(int x, int c) {
    for (int i = 0; i < G[x].size(); i++) {
        int v = G[x][i];
        if (color[v] != c) {
            color[v] = c;
            dfs(v, c);
        }
    }
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n, m, s, u, v;
    cin >> n >> m >> s;
    for (int i = 0; i < m; i++) {
        cin >> u >> v;
        if (v == s) continue;
        G[u].push_back(v);
    }
    memset(color, 0, sizeof(color));
    for (int i = 1; i <= n; i++) {
        if (color[i] == 0) {
            color[i] = i;
            dfs(i, i);
        }
    }
    memset(f, false, sizeof(f));
    int ans = 0;
    for (int i = 1; i <= n; i++) {
        if (!f[color[i]]) ans++;
        f[color[i]] = true;
    }
    cout << ans - 1 << endl;
    return 0;
}

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Cards and Joy

分成若干个子问题，动态规划

#pragma comment(linker, "/STACK:102400000,102400000")
#ifndef ONLINE_JUDGE
#include "stdafx.h"
#else
#include<bits/stdc++.h>
#endif
using namespace std;
typedef long long lint;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef queue<int> QI;
typedef map<int, int> MII;

void makedata() {
    freopen("input.txt", "w", stdout);
    fclose(stdout);
}

int f[600][6000];
int p[150000], h[6000], c[150000], k;
int dp(int n, int m) {
    int rtn = 0;
    for (int i = 0; i <= k; i++) f[0][i] = 0;
    for (int i = 0; i <= n; i++) f[i][0] = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m && j <= i * k; j++) {
            f[i][j] = 0;
            for (int q = 0; q <= k && q <= j; q++) {
                f[i][j] = max(f[i][j], f[i - 1][j - q] + h[q]);
            }
            rtn = max(rtn, f[i][j]);
        }
    }
    return rtn;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    //makedata();
    std::ios::sync_with_stdio(0), cin.tie(0);
    int n, x;
    cin >> n >> k;
    for (int i = 0; i < n * k; i++) {
        cin >> x;
        c[x]++;
    }
    for (int i = 0; i < n; i++) {
        cin >> x;
        p[x]++;
    }
    for (int i = 1; i <= k; i++) cin >> h[i];
    int ans = 0;
    for (int i = 0; i <= 100000; i++) {
        if (p[i] == 0 || c[i] == 0) continue;
        else ans += dp(p[i], c[i]);
    }
    cout << ans << endl;
    return 0;
}

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