2019 ECNU Campus Invitational Contest
作者：互联网
51假期无聊就跟队友一起训练了。队友手感挺好的，反而我不是很在状态。
题目链接：http://codeforces.com/gym/102190
A：
签到题。根据长度暴力塞进去就好了。
1 /* basic header */
2 #include <iostream>
3 #include <cstdio>
4 #include <cstdlib>
5 #include <string>
6 #include <cstring>
7 #include <cmath>
8 #include <cstdint>
9 #include <climits>
10 #include <float.h>
11 /* STL */
12 #include <vector>
13 #include <set>
14 #include <map>
15 #include <queue>
16 #include <stack>
17 #include <algorithm>
18 #include <array>
19 #include <iterator>
20 /* define */
21 #define ll long long
22 #define dou double
23 #define pb emplace_back
24 #define mp make_pair
25 #define fir first
26 #define sec second
27 #define sot(a,b) sort(a+1,a+1+b)
28 #define rep1(i,a,b) for(int i=a;i<=b;++i)
29 #define rep0(i,a,b) for(int i=a;i<b;++i)
30 #define repa(i,a) for(auto &i:a)
31 #define eps 1e-8
32 #define int_inf 0x3f3f3f3f
33 #define ll_inf 0x7f7f7f7f7f7f7f7f
34 #define lson curPos<<1
35 #define rson curPos<<1|1
36 /* namespace */
37 using namespace std;
38 /* header end */
39
40 const int maxn = 10;
41 char s[maxn];
42
43 int main()
44 {
45 scanf("%s", s + 1);
46 int len = strlen(s + 1);
47 int sh = 0, th = 0, day;
48 if (len == 3)
49 {
50 sh = s[1] - '0'; th = 12 + s[2] - '0'; day = s[3] - '0';
51 }
52 else if (len == 5)
53 {
54 sh = (s[1] - '0') * 10 + s[2] - '0';
55 th = 12 + (s[3] - '0') * 10 + s[4] - '0';
56 day = s[5] - '0';
57 }
58 else
59 {
60 sh = (s[1] - '0') * 10 + s[2] - '0';
61 th = 12 + s[3] - '0';
62 day = s[4] - '0';
63 if ((sh < 2 || sh > 11) || (th < 14 || th > 23))
64 {
65 sh = s[1] - '0';
66 th = 12 + (s[2] - '0') * 10 + s[3] - '0';
67 }
68 }
69 printf("%d\n", day * (th - sh));
70 return 0;
71 }
View Code
B：
概率dp。
1 #include <cstdio>
2
3 char A[1000002], B[1000002];
4 double f[1000002], p[1000002];
5
6 int main(void)
7 {
8 int T;
9 scanf("%d", &T);
10 f[0] = 0; // joker in my hand.
11 p[0] = 1; // joker in opp's hand.
12 for (int i = 1; i <= 1000000; i++)
13 {
14 // 我赢的概率 = 1 - 对手在下一个状态下赢的概率
15 f[i] = 1.0 - p[i - 1]; // 我一定会抽到一张好牌；
16 //p[i] = 1.0 / (i + 1) * (1 - p[i]) // 我抽到了对面的鬼牌。
17 // + 1.0 * i / (i + 1) * (1 - f[i - 1]); // 我抽到了对面的好牌。
18 p[i] = (1.0 + i - 1.0 * i * f[i - 1]) / (i + 2);
19 }
20 while (T--)
21 {
22 int n;
23 scanf("%d", &n);
24 scanf(" %s", A);
25 scanf(" %s", B);
26 int cnt = 0;
27 bool myjoker = false;
28 for (int i = 0; i < n; i++)
29 {
30 if (A[i] == '1' && B[i] == '1')
31 {
32 cnt++;
33 }
34 else if (A[i] == '1')
35 {
36 myjoker = true;
37 }
38 }
39 //printf("both: %d, myjoker: %d \n", cnt, myjoker ? 1 : 0);
40 printf("%.10f\n", myjoker ? f[cnt] : p[cnt]);
41 }
42 return 0;
43 }
View Code
C：
队友嘴炮完（但是并没有敲完）的构造题。
D：
看了完全莫得想法的题目，感觉有点像是贪心？
E：
某个队友上来就表示这题很可写，然后被我劝去做B了，最后没搞出来。
F：
傻逼题，题意题。
1 #include<bits/stdc++.h>
2 #define ll long long
3
4 using namespace std;
5
6 map<string, int> M;
7 vector<string> v;
8
9 int main()
10 {
11 int t;
12 cin >> t;
13 while (t)
14 {
15 string x;
16 getline(cin, x);
17 if (x == "") continue;
18 string tmp = "";
19 for (int i = 0; i < x.length(); i++)
20 {
21 if ('A' <= x[i] && x[i] <= 'Z')
22 {
23 tmp += x[i];
24 }
25 }
26 M[tmp] ++ ;
27 if (M[tmp] == 1)
28 {
29 v.push_back(tmp);
30 }
31 t--;
32 }
33 ll ans = 0;
34 for (int i = 0; i < v.size(); i++)
35 {
36 ll x = M[v[i]];
37 ans += x * (x - 1) / 2ll;
38 }
39 cout << ans << endl;
40 return 0;
41 }
View Code
G：
一道很有意思的交互。从n==5的情况出发，先构造出有解的情况，之后再不停地加点上去就可以了。
1 #include <cstdio>
2
3 int main(void)
4 {
5 int T;
6 scanf("%d", &T);
7 while (T--)
8 {
9 int n, st;
10 int st1, st2, st3;
11 scanf("%d", &n);
12 printf("1 2 2 3\n");
13 fflush(stdout);
14 scanf("%d", &st1);
15 printf("3 4 4 5\n");
16 fflush(stdout);
17 scanf("%d", &st2);
18 if (st1 == st2)
19 {
20 printf("5 1 1 4\n");
21 fflush(stdout);
22 scanf("%d", &st3);
23 if (st1 == st3)
24 {
25 printf("1 3 3 5\n");
26 fflush(stdout);
27 scanf("%d", &st);
28 }
29 else
30 {
31 printf("2 5 5 3\n");
32 fflush(stdout);
33 scanf("%d", &st);
34 }
35 }
36 else
37 {
38 printf("5 3 3 1\n");
39 fflush(stdout);
40 scanf("%d", &st3);
41 if (st1 == st3)
42 {
43 printf("1 5 5 2\n");
44 fflush(stdout);
45 scanf("%d", &st);
46 }
47 else
48 {
49 printf("1 5 1 4\n");
50 fflush(stdout);
51 scanf("%d", &st);
52 }
53 }
54 for (int i = 6; i <= n; i++)
55 {
56 printf("%d 1 %d 2\n", i, i);
57 fflush(stdout);
58 scanf("%d", &st);
59 }
60 }
61 return 0;
62 }
View Code
H：
分情况讨论就可以了。
1 #include<bits/stdc++.h>
2
3 using namespace std;
4
5 typedef long long ll;
6
7 ll gcd(ll a, ll b)
8 {
9 if (a % b == 0) return b;
10 else return gcd(b, a % b);
11 }
12
13 int main()
14 {
15 ll h, m;
16 cin >> h >> m;
17 if (h <= m)
18 {
19 ll x1 = h;
20 ll x2 = 2ll * m - h + 1;
21 ll a = x1 * x2 / 2ll;
22 ll b = h * m;
23 ll g = gcd(a, b);
24 a /= g; b /= g;
25 cout << a << '/' << b << endl;
26 }
27 else
28 {
29 ll a = m * (m + 1) / 2ll;
30 ll b = h * m;
31 ll g = gcd(a, b);
32 a /= g; b /= g;
33 cout << a << '/' << b << endl;
34 }
35
36 return 0;
37 }
View Code
I：
队友没发现输入并不保证正确，wa了好多发……
解法倒是非常傻，floyd就完事了。
1 #include<bits/stdc++.h>
2
3 using namespace std;
4
5 const int maxn = 2000;
6 const int INF = 1e5;
7
8 int A[maxn][maxn];
9 int f[maxn][maxn];
10
11 int main()
12 {
13 int T;
14 scanf("%d", &T);
15 while (T--)
16 {
17 int n, fg = 0;
18 scanf("%d", &n);
19 for (int i = 1; i <= n; i++)
20 for (int j = 1; j <= n; j++)
21 {
22 scanf("%d", &A[i][j]);
23 f[i][j] = A[i][j]; //copy
24 }
25 for (int i = 1; i <= n; i++)
26 {
27 f[i][i] = 0; //dui jiao must be zero
28 for (int j = 1; j <= n; j++)
29 {
30 if (f[i][j] != -1 && f[j][i] != -1 && f[i][j] != f[j][i])
31 {
32 fg = 1; goto mark;
33 }
34 if (f[i][j] == -1 && f[j][i] != -1)
35 f[i][j] = f[j][i];
36 else if (f[i][j] == -1) f[i][j] = INF;
37 }
38 }
39 //floyd
40 for (int k = 1; k <= n; k++)
41 for (int i = 1; i <= n; i++)
42 for (int j = 1; j <= n; j++)
43 f[i][j] = min(f[i][k] + f[k][j], f[i][j]);
44 for (int i = 1; i <= n; i++)
45 for (int j = 1; j <= n; j++)
46 {
47 if (A[i][j] != -1 && f[i][j] != A[i][j])
48 {
49 fg = 1;
50 goto mark;
51 }
52 }
53 mark:;
54 if (fg) printf("NO\n");
55 else
56 {
57 printf("YES\n");
58 for (int i = 1; i <= n; i++)
59 {
60 for (int j = 1; j <= n; j++)
61 {
62 if (j == 1) printf("%d", f[i][j]);
63 else
64 {
65 printf(" %d", f[i][j]);
66 }
67 }
68 printf("\n");
69 }
70 }
71 }
72 return 0;
73 }
View Code
J && K：
没看。
L：
还没看就被队友秒了，说是sb贪心（还抢了gym的一血
1 #include<bits/stdc++.h>
2
3 using namespace std;
4 int A[20];
5
6 int main()
7 {
8 int T;
9 scanf("%d", &T);
10 while (T--)
11 {
12 for (int i = 1; i <= 6; i++)
13 scanf("%d", &A[i]);
14 int ans = A[6];
15 A[6] = 0;
16 ans += A[5];
17 A[1] -= A[5];
18 ans += A[4];
19 if (A[2] <= A[4])
20 {
21 A[4] -= A[2];
22 A[2] = 0;
23 A[1] -= A[4] * 2;
24 }
25 else
26 {
27 A[2] -= A[4];
28 }
29 ans += A[3] / 2;
30 A[3] %= 2;
31 if (A[3] == 1)
32 {
33 ans ++;
34 int x = 3;
35 if (A[2] >= 1)
36 {
37 A[2] --;
38 x -= 2;
39 }
40 A[1] -= x;
41 }
42 ans += A[2] / 3;
43 A[2] %= 3;
44 if (A[2] >= 1)
45 {
46 ans ++;
47 A[1] -= 6 - A[2] * 2;
48 }
49 if (A[1] >= 1) ans += (A[1] + 5) / 6;
50 printf("%d\n", ans);
51 }
52 return 0;
53 }
View Code
标签：Invitational,Contest,int,scanf,2019,printf,fflush,include,define 来源： https://www.cnblogs.com/JHSeng/p/10803149.html