正睿20秋季普转提day4

估分：100+100+0+100=300

实际：15+80+0+90=195

T1:

　　代码写炸了，不会写暴力，没拍

　　就拓扑排序，优先队列存一下点的编号就行了

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<vector>
 4 #include<queue>
 5 #include<iostream>
 6 #include<algorithm>
 7 using namespace std;
 8 
 9 const int N = 100010;
10 
11 int n, m, p;
12 int deg[N], top[N];
13 vector<int> e[N];
14 priority_queue<int> que;
15 
16 void init()
17 {
18     for (int i = 1; i <= n; i++)
19     {
20         e[i].clear();
21         deg[i] = 0;
22     }
23 }
24 
25 int main()
26 {
27     int T;
28     scanf("%d", &T);
29     while (T--)
30     {
31         scanf("%d%d", &n, &m);
32         n = abs(n);
33 
34         init();
35             
36         for (int i = 1, x, y; i <= m; i++)
37         {
38             scanf("%d%d", &x, &y);
39             e[y].push_back(x);
40             deg[x]++;
41         }
42             
43         for (int i = 1; i <= n; i++) if (!deg[i]) que.push(i);
44         for (p = 0; !que.empty();)
45         {
46             int x = que.top(); 
47             que.pop(); 
48             top[++p] = x;
49             for (int y : e[x])
50             {
51                 if (!--deg[y])
52                 {
53                     que.push(y);
54                 }
55             }
56         }
57 
58         if (p < n) printf("Impossible!");
59         else for (; n;) printf("%d ", top[n--]);
60         puts("");
61     }
62 }

View Code

T2:

　　常数大了+没开longlong=最后两个点没了

　　每个a改变一位存进哈希表，每个b改变一位查询一次，再把a=b的情况减掉即可

 1 #include<cstdio>
 2 #include<cstring>
 3 #include <map>
 4 #include <iostream>
 5 #include <algorithm>
 6 using namespace std;
 7 
 8 typedef long long LL;
 9 
10 const int N = 100010;
11 
12 int n, m;
13 int a[N], b[N];
14 int A[N * 30], B[N * 30], cnta, cntb;
15 map <int, int> st;
16 
17 int main()
18 {
19     scanf("%d%d", &n, &m);
20     for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
21     for (int i = 1; i <= m; i++) scanf("%d", &b[i]);
22 
23     for (int i = 1; i <= n; i++)
24     {
25         for (int j = 0; j < 30; j++)
26         {
27             A[++cnta] = a[i] ^ (1 << j);
28         }
29     }
30     for (int i = 1; i <= m; i++)
31     {
32         for (int j = 0; j < 30; j++)
33         {
34             B[++cntb] = b[i] ^ (1 << j);
35         }
36     }
37             
38     sort(A + 1, A + cnta + 1);
39     sort(B + 1, B + cntb + 1);
40 
41     LL ans = 0;
42     int id1 = 1, id2 = 1;
43     for (int i = 1; i <= cnta; i++)
44     {
45         while (id1 <= cntb && B[id1] < A[i]) ++id1;
46         while (id2 <= cntb && B[id2] <= A[i]) ++id2;
47         if (B[id1] == A[i]) ans += id2 - id1;
48     }
49     for (int i = 1; i <= n; i++) ++st[a[i]];
50     for (int i = 1; i <= m; i++) ans -= st[b[i]] * 30;
51     cout << ans / 2;
52 }

View Code

T3：

　　不会

T4:

　　暑假联赛班day5原题，写的时候出了点问题，丢了10分

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 
 7 const int N = 100010;
 8 
 9 int n, m;
10 int a[N], b[N], c[N];
11 int f[2][N], q[N];
12 
13 int main()
14 {
15     int T;
16     scanf("%d", &T);
17     while (T--)
18     {
19         scanf("%d%d", &n, &m);
20         if (m < 0) { puts("1"); continue; }
21 
22         for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
23         for (int i = 1; i <= n; ++i) scanf("%d", &b[i]);
24         for (int i = 1; i <= n; ++i) scanf("%d", &c[i]);
25 
26         for (int j = 1; j <= m; ++j) f[0][j] = 2e9 + 1; f[0][0] = 0;
27 
28         int x, y, l, r;
29         for (int i = 1; i <= n; ++i)
30         {
31             x = i & 1, y = x ^ 1, l = 1, r = 0;
32             for (int j = 0; j <= m; j++)  f[x][j] = f[y][j];
33             for (int j = a[i]; j <= m; ++j)
34             {
35                 while (l <= r && q[l] < j - b[i]) ++l;
36                 while (l <= r && f[y][q[r]] >= f[y][j - a[i]]) --r;
37                 q[++r] = j - a[i];
38                 f[x][j] = min(f[x][j], f[y][q[l]] + c[i]);
39             }
40         }
41         if (f[x][m] <= 2e9) printf("%d\n", f[x][m]);
42         else puts("IMPOSSIBLE!!!");
43     }
44     return 0;
45 }

View Code

总结：

　　代码还是容易写炸，暴力的写法得多写；常数的问题也要多注意，之后再看看常数优化，感觉我常数优化要么几乎没变要么负优化。写的时候还得细心点，第三题就代码顺序出了点问题，丢了10分

posted on 2020-10-18 17:52 ArrogHie 阅读(138) 评论(0) 编辑收藏举报