Codeforces Round #644 (Div. 3)

Posted 2020-12-10 wstong

目录

• A - Minimal Square
• B - Honest Coach
• C - Similar Pairs
• D - Buying Shovels
• E - Polygon
• F - Spy-string
• G - A/B Matrix
• H - Binary Median

A - Minimal Square

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e4+5;
int main() {
    int t; cin >> t;
    while (t--) {
        int a, b; cin >> a >> b;
        if (a > b) swap(a,b);
        a <<= 1;
        int ans = max(a,b)*max(a,b);
        cout << ans << endl;
    }
    return 0;
}

B - Honest Coach

#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
int a[maxn];
int main() {
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        for (int i = 1; i <= n; ++i) cin >> a[i];
        sort(a+1,a+1+n);
        int ans = 1e9;
        for (int i = 2; i <= n; ++i) {
            ans = min(ans,a[i]-a[i-1]);
        }
        cout << ans << endl;
    }
    return 0;
}

C - Similar Pairs

#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
int a[maxn];
int main() {
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        for (int i = 1; i <= n; ++i) cin >> a[i];
        int x = 0, y = 0;
        for (int i = 1; i <= n; ++i) {
            if (a[i] & 1) x++;
            else y++;
        }
        if (x % 2 == 0 && y % 2 == 0) cout << "YES" << endl;
        else {
            sort(a+1,a+1+n);
            bool flag = false;
            for (int i = 2; i <= n; ++i) {
                if (a[i] - a[i-1] == 1) {
                    flag = true;
                    break;
                }
            }
            if (flag) cout << "YES" << endl;
            else cout << "NO" << endl;
        }
    }
    return 0;
}

D - Buying Shovels

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
    int t; cin >> t;
    while (t--) {
        int n, k; cin >> n >> k;
        if (k >= n) cout << 1 << endl;
        else {
            int x = sqrt(n);
            int ans = n;
            for (int i = 2; i <= x; ++i) {
                if (n % i == 0) {
                    if (k >= i) ans = min(ans,n/i);
                    if (k >= n/i) ans = min(ans,i);
                }
            }
            cout << ans << endl;
        }
    }
    return 0;
}

E - Polygon

#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
int a[maxn][maxn];
int main() {
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        for (int i = 1; i <= n; ++i) {
            string s; cin >> s;
            for (int j = 1; j <= n; ++j) {
                a[i][j] = s[j-1]-‘0‘;
            }
        }
        bool flag = true;

        for (int i = n-1; i >= 1; --i) {
            for (int j = 1; j <= i; ++j) {
                if (a[i][j] == 1 && a[i+1][j] == 0 && a[i][j+1] == 0) {
                    flag = false;
                    break;
                }
            }
            for (int j = 1; j <= i; ++j) {
                if (a[j][i] == 1 && a[j][i+1] == 0 && a[j+1][i] == 0) {
                    flag = false;
                    break;
                }
            }
            if (flag == false) break;
        }

        if (flag) cout << "YES" << endl;
        else cout << "NO" << endl;
    }
    return 0;
}

F - Spy-string

#include <bits/stdc++.h>
using namespace std;
const int maxn = 15;
string s[maxn];
int n, m;
bool check(int x) {
    int cnt = 0;
    for (int i = 0; i < m; ++i) {
        if (s[0][i] != s[x][i]) cnt++;
        if (cnt > 1) return false;
    }
    return true;
}
int main() {
    int t; cin >> t;
    while (t--) {
        cin >> n >> m;
        for (int i = 1; i <= n; ++i) cin >> s[i];
        for (int j = 0; j < m; ++j) {
            s[0] = s[1];
            for (char k = ‘a‘; k <= ‘z‘; ++k) {
                s[0][j] = k;
                bool flag = true;
                for (int i = 2; i <= n; ++i) {
                    if (check(i) == false) {
                        flag = false;
                        break;
                    }
                }
                if (flag) {
                    cout << s[0] << endl;
                    s[0] = "";
                    break;
                }
            }
            if (s[0] == "") break;
        }
        if (s[0] != "") cout << -1 << endl;
    }
    return 0;
}

G - A/B Matrix

#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
int mat[maxn][maxn];
int main() {
    int t; cin >> t;
    while (t--) {
        int n, m, a, b; cin >> n >> m >> a >> b;
        if (n*a != m*b) cout << "NO" << endl;
        else {
            memset(mat,0,sizeof(mat));
            cout << "YES" << endl;
            int x = 0;
            for (int i = 0; i < n; ++i) {
                for (int j = 0; j < a; ++j) {
                    mat[i][x] = 1;
                    x++;
                    x %= m;
                }
            }
            for (int i = 0; i < n; ++i) {
                for (int j = 0; j < m; ++j) {
                    cout << mat[i][j];
                }
                cout << endl;
            }
        }
    }
    return 0;
}

H - Binary Median

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll bin2dec(string s) {
    ll res = 0;
    int len = s.size();
    for (int i = 0; i < len; ++i) {
        res += (s[i]-‘0‘) * pow(2, len-i-1);
    }
    return res;
}
int main() {
    int t; cin >> t;
    while (t--) {
        ll n, m; cin >> n >> m;
        ll mid = (1ll << (m-1));  // 一开始的中位数
        vector<ll> ve;
        for (ll i = -100; i < 100; ++i) {
            ve.push_back(mid+i);
        }
        for (int i = 1; i <= n; ++i) {
            string s; cin >> s;
            ll x = bin2dec(s);
            if (x <= ve.front()) ve.erase(ve.begin());
            else if (x >= ve.back()) ve.erase(ve.end()-1);
            else ve.erase(lower_bound(ve.begin(),ve.end(),x));
        }
        ll x = ve[(ve.size()-1)/2];
        for (ll i = m-1; i >= 0; --i) {
            if ((1ll << i) & x) cout << 1;
            else cout << 0;
        }
        cout << endl;
    }
    return 0;
}