Codeforces Round #600 (Div. 2)

Codeforces Round #600 (Div. 2)

A. Single Push

• 思路：水题

• AC代码

---

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

ll mult_mod(ll x, ll y, ll mod){
    return (x * y - (ll)(x / (long double)mod * y + 1e-3) * mod + mod) % mod;
}

ll pow_mod(ll a, ll b, ll p){
    ll res = 1;
    while (b){
        if (b & 1)
            res = mult_mod(res, a, p);
        a = mult_mod(a, a, p);
        b >>= 1;
    }
    return res % p;
}

ll gcd(ll a, ll b){
    return b ? gcd(b, a % b) : a;
}

const int N = 1e5 + 10;

int t, n;
int a[N], b[N];

int main(){
#ifndef ONLINE_JUDGE
    freopen("my_in.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> t;
    while (t -- ){
        cin >> n;
        for (int i = 1; i <= n; i ++ )
            cin >> a[i];
        for (int i = 1; i <= n; i ++ ){
            cin >> b[i];
            b[i] -= a[i];
        }
        vector<int> c;
        bool flag1 = true;
        int pos1 = 0, pos2 = 0;
        for (int i = 1; i <= n; i ++ ){
            if (b[i] < 0){
                flag1 = false;
                break;
            }
        }
        if (!flag1){
            cout << "NO
";
            continue;
        }
        for (int i = 1; i <= n; i ++ ){
            if (b[i] != 0){
                pos1 = i;
                break;
            }
        }
        for (int i = n; i >= 1; i -- ){
            if (b[i] != 0){
                pos2 = i;
                break;
            }
        }
        for (int i = pos1; i <= pos2; i ++ )
            c.push_back(b[i]);
        bool flag2 = true;
        for (int i = 0; i < c.size() - 1; i ++ ){
            if (c[i] != c[i + 1]){
                flag2 = false;
                break;
            }
        }
        if (!flag2){
            cout << "NO
";
            continue;
        }
        cout << "YES
";
    }
    return 0;
}

B. Silly Mistake

• 思路：模拟

• AC代码

---

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

ll mult_mod(ll x, ll y, ll mod){
    return (x * y - (ll)(x / (long double)mod * y + 1e-3) * mod + mod) % mod;
}

ll pow_mod(ll a, ll b, ll p){
    ll res = 1;
    while (b){
        if (b & 1)
            res = mult_mod(res, a, p);
        a = mult_mod(a, a, p);
        b >>= 1;
    }
    return res % p;
}

ll gcd(ll a, ll b){
    return b ? gcd(b, a % b) : a;
}

const int N = 1e5 + 10;

int n, a, c1, c2, tot;
int b[N];
map<int, int> mp1, mp2;

int main(){
#ifndef ONLINE_JUDGE
    freopen("my_in.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i ++ ){
        cin >> a;
        if (a > 0){
            if (mp1[a] != 0)
                c1 = 1;
            else{
                if (mp2[a] != 0)
                    c1 = 1;
                mp1[a] ++ ;
                mp2[a] ++ ;
                c2 ++ ;
            }
        }
        else{
            if (mp1[-a] == 0)
                c1 = 1;
            else{
                mp1[-a] -- ;
                c2 -- ;
                if (!c2){
                    b[ ++ tot ] = i;
                    mp2.clear();
                }
            }
        }
    }
    if (c1 == 1 || c2 != 0){
        cout << "-1
";
        return 0;
    }
    cout << tot << "
";
    for (int i = 1; i <= tot; i ++ )
        cout << b[i] - b[i - 1] << " ";
    return 0;
}

C. Sweets Eating

• 思路：贪心 排序后求前缀和搞搞

• AC代码

---

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

ll mult_mod(ll x, ll y, ll mod){
    return (x * y - (ll)(x / (long double)mod * y + 1e-3) * mod + mod) % mod;
}

ll pow_mod(ll a, ll b, ll p){
    ll res = 1;
    while (b){
        if (b & 1)
            res = mult_mod(res, a, p);
        a = mult_mod(a, a, p);
        b >>= 1;
    }
    return res % p;
}

ll gcd(ll a, ll b){
    return b ? gcd(b, a % b) : a;
}

const int N = 2e5 + 10;

int n, m;
int a[N];
ll sum[N], ans[N];

int main(){
#ifndef ONLINE_JUDGE
    freopen("my_in.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i ++ )
        cin >> a[i];
    sort(a + 1, a + n + 1);
    for (int i = 1; i <= n; i ++ ){
        sum[i] = sum[i - 1] + 1ll * a[i];
        if (i <= m)
            ans[i] = sum[i];
        else
            ans[i] = ans[i - m] + sum[i];
    }
    for (int i = 1; i <= n; i ++ )
        cout << ans[i] << " ";
    return 0;
}

D. Harmonious Graph

• 思路：bfs遍历找到一个端点可以连到的最远点 找直接不能连通的点每次ans ++ 然后更新连通性即可

• AC代码

---

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

ll mult_mod(ll x, ll y, ll mod){
    return (x * y - (ll)(x / (long double)mod * y + 1e-3) * mod + mod) % mod;
}

ll pow_mod(ll a, ll b, ll p){
    ll res = 1;
    while (b){
        if (b & 1)
            res = mult_mod(res, a, p);
        a = mult_mod(a, a, p);
        b >>= 1;
    }
    return res % p;
}

ll gcd(ll a, ll b){
    return b ? gcd(b, a % b) : a;
}

const int N = 2e5 + 10;

int n, m, maxx, tot, ans;
int vis[N], head[N];

struct Edge{
    int v, nxt;
}e[N << 1];

void add(int u, int v){
    e[ ++ tot ].v = v;
    e[tot].nxt = head[u];
    head[u] = tot;
}

void bfs(int x){
    vis[x] = true;
    maxx = max(maxx, x);
    queue<int> q;
    q.push(x);
    while (!q.empty()){
        int u = q.front();
        q.pop();
        for (int i = head[u]; i; i = e[i].nxt){
            int v = e[i].v;
            if (vis[v])
                continue;
            q.push(v);
            vis[v] = true;
            maxx = max(maxx, v);
        }
    }
}

int solve(int x){
    int res = 0;
    bfs(x);
    for (int i = x + 1; i < maxx; i ++ ){
        if (!vis[i]){
            res ++ ;
            bfs(i);
        }
    }
    return res;
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("my_in.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= m; i ++ ){
        int u, v;
        cin >> u >> v;
        add(u, v);
        add(v, u);
    }
    for (int i = 1; i <= n; i ++ )
        if (!vis[i])
            ans += solve(i);
    cout << ans << "
";
    return 0;
}