Codeforces Round #614 (Div. 2)

Posted 2021-03-14 jhseng

很简单的一场，暴力又白给。值得一提的是这场题目背景居然是CytusII

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A：

一开始还想用golang写的，后来发现不会golang的数据结构，于是老老实实滚回c++了。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 int t, n, s, k;
21 set<int>a;
22 
23 int main() {
24     scanf("%d", &t);
25     while (t--) {
26         a.clear();
27         scanf("%d%d%d", &n, &s, &k);
28         for (int i = 1; i <= k; i++) {
29             int x; scanf("%d", &x);
30             a.insert(x);
31         }
32         int ans = 0;
33         while (1) {
34             if (s + ans <= n && !a.count(s + ans)) break;
35             if (s - ans > 0 && !a.count(s - ans)) break;
36             ans++;
37         }
38         printf("%d
", ans);
39     }
40     return 0;
41 }

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B：

显然每次淘汰一个人能赚到的最多。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 int n;
21 
22 int main() {
23     scanf("%d", &n);
24     double ans = 0;
25     for (int i = 1; i <= n; i++) ans += 1.0 / (double)i;
26     printf("%.6f
", ans);
27     return 0;
28 }

View Code

C：

每次加点删点维护一下建了或摧毁了多少堵“墙”就行。

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 const int maxn = 1e5 + 10;
21 int a[2][maxn], n, q, wall = 0;
22 
23 void solve(int x, int y) {
24     if (a[x][y]) {
25         if (a[x ^ 1][y - 1]) wall--;
26         if (a[x ^ 1][y]) wall--;
27         if (a[x ^ 1][y + 1]) wall--;
28     } else {
29         if (a[x ^ 1][y - 1]) wall++;
30         if (a[x ^ 1][y]) wall++;
31         if (a[x ^ 1][y + 1]) wall++;
32     }
33     a[x][y] = a[x][y] ^ 1;
34 }
35 
36 int main() {
37     scanf("%d%d", &n, &q);
38     for (int i = 0; i <= n; i++) a[0][i] = a[1][i] = 0;
39     while (q--) {
40         int x, y; scanf("%d%d", &x, &y);
41         x--;
42         solve(x, y);
43         if (!wall) puts("Yes");
44         else puts("No");
45     }
46     return 0;
47 }

View Code

D：

很无聊的爆搜。

 1 #include <bits/stdc++.h>
 2 #define ll long long
 3 
 4 using namespace std;
 5 
 6 const ll inf = 1e17;
 7 ll x[105], y[105];
 8 ll ax, ay, bx, by, a, b, t;
 9 int n, ans = 0;
10 
11 int main(void) {
12     ios_base::sync_with_stdio(0);
13     cin.tie(NULL);
14     cin >> x[0] >> y[0] >> ax >> ay >> bx >> by;
15     // 跑到直到爆边界
16     while (x[n] < inf && y[n] < inf) {
17         ++n;
18         // 不符合要求
19         if (x[n - 1] > (inf - bx) / ax + 1 || y[n - 1] > (inf - by) / ay + 1) {
20             --n;
21             break;
22         }
23         x[n] = ax * x[n - 1] + bx;
24         y[n] = ay * y[n - 1] + by;
25     }
26     cin >> a >> b >> t;
27     // 枚举每个点
28     for (int i = 0; i <= n; ++i) {
29         ll currDis = abs(x[i] - a) + abs(y[i] - b);
30         if (currDis > t) continue;
31         ll remainLen = t - currDis;
32         // O(n^2)枚举前面的两点
33         for (int l = 0; l <= i; ++l) {
34             for (int r = i; r <= n; ++r) {
35                 currDis = abs(x[i] - x[l]) + abs(y[i] - y[l]);
36                 currDis = min(currDis, abs(x[i] - x[r]) + abs(y[i] - y[r]));
37                 currDis += abs(x[l] - x[r]) + abs(y[l] - y[r]);
38                 // 剩下的长度能走完则符合要求
39                 if (currDis <= remainLen) ans = max(ans, r - l + 1);
40             }
41         }
42     }
43     cout << ans << endl;
44     return 0;
45 }

better one

 1 /* basic header */
 2 #include <bits/stdc++.h>
 3 /* define */
 4 #define ll long long
 5 #define dou double
 6 #define pb emplace_back
 7 #define mp make_pair
 8 #define sot(a,b) sort(a+1,a+1+b)
 9 #define rep1(i,a,b) for(int i=a;i<=b;++i)
10 #define rep0(i,a,b) for(int i=a;i<b;++i)
11 #define eps 1e-8
12 #define int_inf 0x3f3f3f3f
13 #define ll_inf 0x7f7f7f7f7f7f7f7f
14 #define lson (curpos<<1)
15 #define rson (curpos<<1|1)
16 /* namespace */
17 using namespace std;
18 /* header end */
19 
20 ll xZero, yZero, ax, ay, bx, by, sx, sy, t;
21 
22 ll getDis(ll x0, ll y0, ll x1, ll y1) {
23     return abs(x0 - x1) + abs(y0 - y1);
24 }
25 
26 int main() {
27     scanf("%lld%lld%lld%lld%lld%lld", &xZero, &yZero, &ax, &ay, &bx, &by);
28     scanf("%lld%lld%lld", &sx, &sy, &t);
29     ll xi = xZero, yi = yZero, xj, yj, xp = xZero, yp = yZero, i = 0, j = 0, p = 0, ans = 0;
30     ll currDis = getDis(xi, yi, sx, sy), lastDis = currDis + 1;
31     while (currDis > t && lastDis > currDis) {
32         xi = xi * ax + bx, yi = yi * ay + by, i++, lastDis = currDis;
33         // calculate distance of each point to start point
34         currDis = getDis(xi, yi, sx, sy);
35         while (currDis + getDis(xi, yi, xp, yp) > t && p <= i) {
36             xp = xp * ax + bx, yp = yp * ay + by, p++;
37         }
38     }
39     j = i; xj = xi; yj = yi;
40     while (currDis <= t) {
41         while (currDis + getDis(xi, yi, xj, yj) <= t) {
42             xj = xj * ax + bx, yj = yj * ay + by, j++;
43         }
44         ans = max(ans, j - i);
45         while (currDis + getDis(xi, yi, xp, yp) > t) {
46             xp = xp * ax + bx, yp = yp * ay + by, p++;
47         }
48         ans = max(ans, i - p + 1);
49         xi = xi * ax + bx, yi = yi * ay + by, i++;
50         currDis = getDis(xi, yi, sx, sy);
51     }
52     printf("%lld
", ans);
53 
54 }

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