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。
把简单的题都切了，剩下的都是通过人数个位数的神仙题。
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 }
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 }
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 }
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 }
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 }
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 }
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 }