Educational Codeforces Round 15
Educational Codeforces Round 15
https://codeforces.com/contest/702
3/6:ABC 不会小学数学，基础差前面写的慢
A. Maximum Increase
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int a[N], n, ans, len = 1;
int main () {
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i];
for (int i = 2; i <= n; i++) {
if (a[i] > a[i-1]) len ++;
else {
ans = max (ans, len);
len = 1;
}
}
ans = max (ans, len);
cout << ans;
}
B. Powers of Two
#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef pair<int, int> pii;
const int N = 1e5 + 5;
int a[N], n, ans;
int pw2[] = {2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648};
signed main () {
map<int, int> mp;
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i], mp[a[i]] ++;
sort (a + 1, a + n + 1);
//for (int i = 1; i <= n; i++) cout << a[i] << ' '; cout << endl;
// int x = 1;
// while (x <= 2e9) {
// x *= 2;
// cout << x << ", ";
// }
for (int i = 1; i < n; i++) {
mp[a[i]] --;
//可以取到的范围: [a[i]+a[i+1], a[i]+a[n]]
int l = a[i] + a[i+1], r = a[i] + a[n];
int ed = *lower_bound (pw2, pw2 + 31, r);
int st = *lower_bound (pw2, pw2 + 31, l); //[st, ed)
//cout << st << ' ' << ed << endl;
for (int j = st; j <= ed; j *= 2) {
int find = j - a[i]; //找有多少个
ans += mp[find];
}
}
cout << ans << endl;
}
C. Cellular Network
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 1e5 + 5, inf = 1e9 + 5;
int a[N], n, m, x, ans, dist;
signed main () {
vector <int> b;
cin >> n >> m;
for (int i = 1; i <= n; i++) cin >> a[i];
for (int i = 1; i <= m; i++) cin >> x, b.push_back (x);
sort (b.begin (), b.end ());
//for (int i = 1; i <= m; i++) cout << b[i] << ' '; cout << endl;
for (int i = 1; i <= n; i++) {
//二分最近的左右点
auto it = lower_bound (b.begin (), b.end (), a[i]);
if (it == b.end ()) dist = a[i] - *prev(it);
else if (it == b.begin ()) dist = *it - a[i];
else dist = min (*it - a[i], a[i] - *prev(it));
//cout << *l << ' ' << *r << ' ' << dist << endl;
ans = max (ans, dist);
}
cout << ans << endl;
}
//sort b, 二分
//计算每个cly到最近站的距离, 取max
D. Road to Post Office
#include <bits/stdc++.h>
#define int long long
using namespace std;
int d, k, a, b, t, ans; // a车b人
signed main() {
cin >> d >> k >> a >> b >> t;
if (k > d) ans = a * d; //直接开车到了
else {
ans = min(k * a + b * (d - k), d * a + t * (d / k)); //开车k公里, 再走路; 全部开车
ans = min(ans, (d % k) * b + t * (d / k - 1) + a * (d - d % k)); //在最后一次要修车的时候，开始走路
}
cout << ans << endl;
}
//烦人的小学数学题
//坑点：到站了也要修
