Just 3n + 1.
1#include <bits/stdc++.h>
2using namespace std;
3
4#define sz(x) (int(x.size()))
5typedef long long ll;
6typedef double db;
7
8int main() {
9 ll x;
10 while (scanf(" %lld", &x)) {
11 if (x == 0) break;
12 printf("%lld ", x);
13
14 ll mx = -1;
15 int i;
16 for (i = 0; ; i++) {
17 if (x & 1) {
18 x = 3 * x + 1;
19 }
20 else {
21 x = x / 2;
22 }
23 mx = max(mx, x);
24 if (x == 1) {
25 break;
26 }
27 }
28
29 printf("%d %lld\n", i + 1, mx);
30 }
31
32
33 return 0;
34} 1#include <bits/stdc++.h>
2
3using namespace std;
4
5typedef long long ll;
6
7void solve()
8{
9 int n;
10 scanf("%d", &n);
11
12 int inp[n];
13 for(int i = 0; i < n; i++) {
14 scanf("%d", &inp[i]);
15 }
16
17 sort(inp, inp + n);
18
19 // implement
20 // -------++++++++
21 ll product = inp[0] * inp[1];
22 ll ans = LLONG_MIN;
23 for(int i = 2; i < n; i++) {
24 ans = max(ans, product * inp[i]);
25 }
26
27 product = inp[n - 1] * inp[n - 2];
28 for(int i = 0; i < n - 2; i++) {
29 ans = max(ans, product * inp[i]);
30 }
31
32 printf("%lld\n", ans);
33}
34
35int main()
36{
37 int ncase;
38 scanf("%d", &ncase);
39
40 while(ncase--)
41 solve();
42
43 return 0;
44}Ahh…… We can’t do the math with mod inverse… so we resort to enumeration…
1#include <bits/stdc++.h>
2
3using namespace std;
4
5typedef long long ll;
6const ll P = 65537;
7
8ll x[3];
9ll y[3];
10ll cal(ll a0, ll a1, ll a2, int which)
11{
12 ll x_2 = x[which] * x[which] % P;
13 return (((a0 + a1 * x[which]) % P + a2 * x_2) % P);
14}
15
16void solve()
17{
18 for(int i = 0; i < 3; i++)
19 scanf("%lld %lld", &x[i], &y[i]);
20
21 ll x_2 = (x[0] * x[0]) % P;
22 for(ll a1 = 0; a1 < P; a1++) {
23 for(ll a2 = 0; a2 < P; a2++) {
24 ll a0 = 5 * P + y[0] - (a1 * x[0]) % P - (a2 * x_2) % P;
25 a0 %= P;
26 assert(cal(a0, a1, a2, 0) == y[0]);
27
28 if(cal(a0, a1, a2, 1) == y[1] && cal(a0, a1, a2, 2) == y[2]) {
29 printf("%lld %lld %lld\n", a0, a1, a2);
30 return;
31 }
32 }
33 }
34}
35
36int main()
37{
38 int ncase;
39 scanf("%d", &ncase);
40
41 while(ncase--)
42 solve();
43
44 return 0;
45}Problem statement contains error…………..
1#include <bits/stdc++.h>
2using namespace std;
3
4const int S = 4;
5const int INA = 2; // inactive
6const int ADA = 0;
7const int XY = 1;
8const int NON = 3; // nonreachable
9const int ACT = 5; // active
10
11int sx, sy;
12int A[8][8];
13int Z[8][8];
14
15bool xy_check(int tx, int ty) {
16 for (int x = min(sx, tx); x <= max(sx, tx); x++) {
17 if (A[x][sy] == INA) {
18 return false;
19 }
20 }
21 for (int y = min(sy, ty); y <= max(sy, ty); y++) {
22 if (A[tx][y] == INA) {
23 return false;
24 }
25 }
26 return true;
27}
28
29bool ada_check(int tx, int ty) {
30 for (int x = min(sx, tx); x <= max(sx, tx); x++) {
31 for (int y = min(sy, ty); y <= max(sy, ty); y++) {
32 if (A[x][y] == INA) {
33 return false;
34 }
35 }
36 }
37 return true;
38}
39
40void print(int a[8][8]) {
41 for (int y = 0; y < 8; y++) {
42 for (int x = 0; x < 8; x++) {
43 cout << a[x][y];
44 }
45 cout << endl;
46 }
47}
48
49int main() {
50 ios::sync_with_stdio(false);
51 cin.tie(0);
52
53 string s;
54 while (cin >> s) {
55 if (s == "0") break;
56
57 for (int x = 0; x < 8; x++) {
58 for (int y = 0; y < 8; y++) {
59 Z[x][y] = NON;
60 }
61 }
62
63 for (int i = 0; i < 64; i++) {
64 int y = i / 8;
65 int x = i % 8;
66 if (s[i] == '2') {
67 A[x][y] = S;
68 Z[x][y] = S;
69 sx = x;
70 sy = y;
71 } else if (s[i] == '1') {
72 A[x][y] = INA;
73 Z[x][y] = INA;
74 } else {
75 A[x][y] = ACT;
76 }
77 }
78
79 // print(A);
80 // cout << endl;
81
82 for (int x = 0; x < 8; x++) {
83 for (int y = 0; y < 8; y++) {
84 if (x == sx && y == sy) continue;
85 if (xy_check(x, y)) {
86 Z[x][y] = XY;
87 }
88 }
89 }
90
91 for (int x = 0; x < 8; x++) {
92 for (int y = 0; y < 8; y++) {
93 if (x == sx && y == sy) continue;
94 if (ada_check(x, y)) {
95 Z[x][y] = ADA;
96 }
97 }
98 }
99
100 for (int y = 0; y < 8; y++) {
101 for (int x = 0; x < 8; x++) {
102 cout << Z[x][y];
103 }
104 }
105 cout << endl;
106
107 // print(Z);
108 }
109 return 0;
110}I know using graph for this one is overkill, but this is what makes us feel like 1 AC :)
1#include <bits/stdc++.h>
2
3using namespace std;
4
5#define N 10010
6
7typedef pair<int, int> ii;
8
9void solve(int n)
10{
11 int inp[n + 1];
12 for(int i = 1; i <= n; i++)
13 scanf("%d", &inp[i]);
14 // for(int i = 1; i <= n; i++)
15 //printf("%d%c", inp[i], i == n ? '\n' : ' ');
16
17 vector<int> g[N];
18 int in[N] = {0};
19 int out[N] = {0};
20 for(int i = 1; i <= n; i++) {
21 g[i].push_back(inp[i]);
22 in[inp[i]]++;
23 out[i]++;
24 }
25
26 vector<int> s;
27 for(int i = 1; i <= n; i++) {
28 if(in[i] == 0)
29 s.push_back(i);
30 }
31
32 vector<ii> ans;
33 for(int i = 0; i < (int) s.size(); i++) {
34 int cnt = 0;
35 int who = s[i];
36 // printf("cnt %d who %d\n", cnt, who);
37 while((int)g[who].size() > 0) {
38 // printf("cnt %d who %d\n", cnt, who);
39 cnt++;
40 who = g[who][0];
41 }
42
43 ans.push_back(ii(s[i], cnt));
44 }
45 sort(ans.begin(), ans.end());
46
47 printf("%d", (int)ans.size());
48 for(int i = 0; i < (int)ans.size(); i++)
49 printf(" %d %d", ans[i].first, ans[i].second);
50 printf("\n");
51}
52
53int main()
54{
55 int n;
56 while(scanf("%d", &n) == 1 && n)
57 solve(n);
58
59 return 0;
60}