Number Triangles：
/*
DP 题
dp[j] = max(dp[j - 1] + tgl[i-1][j], dp[j] + tgl[i-1][j]);
*/
1 #define _CRT_SECURE_NO_WARNINGS
2 #define HOME
3 #define _CRTDBG_MAP_ALLOC
4 #include <crtdbg.h>
5
6 /*
7 ID: Jming
8 PROG: numtri
9 LANG: C++
10 */
11 #include <iostream>
12 #include <fstream>
13 #include <sstream>
14 #include <cstdlib>
15 #include <cstdio>
16 #include <cstddef>
17 #include <iterator>
18 #include <algorithm>
19 #include <string>
20 #include <locale>
21 #include <cmath>
22 #include <vector>
23 #include <cstring>
24 #include <map>
25 #include <utility>
26 #include <queue>
27 #include <stack>
28 #include <set>
29 #include <functional>
30 using namespace std;
31 typedef pair<int, int> PII;
32 typedef long long int64;
33 const int INF = 0x3f3f3f3f;
34 const int modPrime = 3046721;
35 const double eps = 1e-9;
36 const int MaxN = 510000;
37 const int MaxM = 10010;
38
39
40 int N;
41 int dp[MaxN];
42 vector<vector<int> > tgl;
43
44
45 void Solve()
46 {
47 for (int i = 1; i <= N; ++i)
48 {
49 for (int j = i; j >= 1; --j)
50 {
51 dp[j] = max(dp[j - 1] + tgl[i-1][j], dp[j] + tgl[i-1][j]);
52 }
53 }
54 cout << *max_element(dp, dp + MaxN) << endl;
55 }
56
57 int main()
58 {
59 #ifdef HOME
60 freopen("in", "r", stdin);
61 //freopen("out", "w", stdout);
62 #endif
63
64 freopen("numtri.in", "r", stdin);
65 freopen("numtri.out", "w", stdout);
66
67 fill(dp, dp + MaxN, 0);
68 scanf("%d", &N);
69 for (int i = 1; i <= N; ++i)
70 {
71 vector<int> row;
72 row.push_back(0);
73 int tmp;
74 for (int j = 0; j < i; ++j)
75 {
76 scanf("%d", &tmp);
77 row.push_back(tmp);
78 }
79 tgl.push_back(row);
80 }
81
82 Solve();
83
84 #ifdef HOME
85 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
86 _CrtDumpMemoryLeaks();
87 #endif
88 return 0;
89 }
Prime Palindromes：
/*
生成回文数 + 判断是否为质数
*/
解法一：
1 /*
2 ID: Jming
3 PROG: pprime
4 LANG: C++
5 */
6 #include <iostream>
7 #include <fstream>
8 #include <sstream>
9 #include <cstdlib>
10 #include <cstdio>
11 #include <cstddef>
12 #include <iterator>
13 #include <algorithm>
14 #include <string>
15 #include <locale>
16 #include <cmath>
17 #include <vector>
18 #include <cstring>
19 #include <map>
20 #include <utility>
21 #include <queue>
22 #include <stack>
23 #include <set>
24 #include <functional>
25 using namespace std;
26 typedef pair<int, int> PII;
27 typedef long long int64;
28 const int INF = 0x3f3f3f3f;
29 const int modPrime = 3046721;
30 const double eps = 1e-9;
31 const int MaxN = 100000010;
32 const int MaxM = 10010;
33
34
35 vector<int> legal;
36
37
38 // 判断是否为质数
39 bool isPrime(int x)
40 {
41 for (int i = 2; i*i <= x; ++i)
42 {
43 if (x%i == 0)
44 {
45 return false;
46 }
47 }
48 return true;
49 }
50
51 // 保存答案
52 void getAns(int x)
53 {
54 if (isPrime(x))
55 {
56 legal.push_back(x);
57 }
58 }
59
60 // 生成回文数
61 void getPdm()
62 {
63 int palindrome;
64
65 for (int i1 = 1; i1 <= 9; i1 += 2)
66 {
67 // 1
68 palindrome = i1;
69 getAns(palindrome);
70 // 2
71 palindrome = i1 * 10 + i1;
72 getAns(palindrome);
73 }
74
75 for (int i1 = 1; i1 <= 9; i1 += 2)
76 {
77 for (int i2 = 0; i2 <= 9; ++i2)
78 {
79 // 3
80 palindrome = i1 * 100 + i2 * 10 + i1;
81 getAns(palindrome);
82 // 4
83 palindrome = i1 * 1000 + i2 * 100 + i2 * 10 + i1;
84 getAns(palindrome);
85 }
86 }
87
88 for (int i1 = 1; i1 <= 9; i1 += 2)
89 {
90 for (int i2 = 0; i2 <= 9; ++i2)
91 {
92 for (int i3 = 0; i3 <= 9; ++i3)
93 {
94 // 5
95 palindrome =
96 i1 * 10000 + i2 * 1000 + i3 * 100 +
97 i2 * 10 + i1;
98 getAns(palindrome);
99 // 6
100 palindrome =
101 i1 * 100000 + i2 * 10000 + i3 * 1000 +
102 i3 * 100 + i2 * 10 + i1;
103 getAns(palindrome);
104 }
105 }
106 }
107
108 for (int i1 = 1; i1 <= 9; i1 += 2)
109 {
110 for (int i2 = 0; i2 <= 9; ++i2)
111 {
112 for (int i3 = 0; i3 <= 9; ++i3)
113 {
114 for (int i4 = 0; i4 <= 9; ++i4)
115 {
116 // 7
117 palindrome =
118 i1 * 1000000 + i2 * 100000 + i3 * 10000 + i4 * 1000 +
119 i3 * 100 + i2 * 10 + i1;
120 getAns(palindrome);
121 // 8
122 palindrome =
123 i1 * 10000000 + i2 * 1000000 + i3 * 100000 + i4 * 10000 +
124 i4 * 1000 + i3 * 100 + i2 * 10 + i1;
125 getAns(palindrome);
126 }
127 }
128 }
129 }
130 }
131
132
133
134 int main()
135 {
136 #ifdef HOME
137 freopen("in", "r", stdin);
138 //freopen("out", "w", stdout);
139 #endif
140
141 freopen("pprime.in", "r", stdin);
142 freopen("pprime.out", "w", stdout);
143
144
145
146 getPdm();
147 sort(legal.begin(), legal.end());
148 int a, b;
149 scanf("%d %d", &a, &b);
150 int i = 0;
151 while (legal[i] < a) ++i;
152 while ((i<legal.size()) && legal[i] <= b)
153 {
154 printf("%d\n", legal[i]);
155 ++i;
156 }
157
158
159
160 #ifdef HOME
161 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
162 _CrtDumpMemoryLeaks();
163 #endif
164 return 0;
165 }
解法二（优化）：
1 /*
2 生成回文数 + 判断是否为质数
3 备注：
4 sprintf：整数转换为字符串
5 atoi：字符串转换为int
6 */
7 /*
8 ID: Jming
9 PROG: pprime
10 LANG: C++
11 */
12 #include <iostream>
13 #include <fstream>
14 #include <sstream>
15 #include <cstdlib>
16 #include <cstdio>
17 #include <cstddef>
18 #include <iterator>
19 #include <algorithm>
20 #include <string>
21 #include <locale>
22 #include <cmath>
23 #include <vector>
24 #include <cstring>
25 #include <map>
26 #include <utility>
27 #include <queue>
28 #include <stack>
29 #include <set>
30 #include <functional>
31 using namespace std;
32 typedef pair<int, int> PII;
33 typedef long long int64;
34 const int INF = 0x3f3f3f3f;
35 const int modPrime = 3046721;
36 const double eps = 1e-9;
37 const int MaxN = 10010;
38 const int MaxM = 10010;
39
40
41 int A, B;
42
43 // 判断是否为质数
44 bool isPrime(int x)
45 {
46 if (x < 2)
47 {
48 return false;
49 }
50 for (int i = 2; i*i <= x; ++i)
51 {
52 if (x%i == 0)
53 {
54 return false;
55 }
56 }
57 return true;
58 }
59
60 void gen(int x, int isOdd)
61 {
62 char buf[10];
63
64 sprintf(buf, "%d", x);
65
66 char *p, *q;
67
68 p = buf + strlen(buf);
69
70 q = p - isOdd;
71
72 while (q > buf)
73 {
74 *(p++) = *(--q);
75 }
76
77 *p = ‘\0‘;
78
79 int n = atoi(buf);
80
81 if ((n >= A) && (n <= B) && (isPrime(n)))
82 {
83 printf("%d\n", n);
84 }
85 }
86
87
88
89 void getPdm(int start, int end)
90 {
91 for (int i = start; i <= end; ++i)
92 {
93 // 生成位数是奇数的回文数
94 gen(i, 1);
95 }
96 for (int i = start; i <= end; ++i)
97 {
98 // 生成位数是偶数的回文数
99 gen(i, 0);
100 }
101 }
102
103 void Solve()
104 {
105 getPdm(1, 9);
106 getPdm(10, 99);
107 getPdm(100, 999);
108 getPdm(1000, 9999);
109 }
110
111 int main()
112 {
113 #ifdef HOME
114 freopen("in", "r", stdin);
115 //freopen("out", "w", stdout);
116 #endif
117
118 freopen("pprime.in", "r", stdin);
119 freopen("pprime.out", "w", stdout);
120
121 scanf("%d %d", &A, &B);
122 Solve();
123
124
125 #ifdef HOME
126 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
127 _CrtDumpMemoryLeaks();
128 #endif
129 return 0;
130 }
Superprime Rib：
/*
此题可利用 “当前生成位数为n的数是否为质数” 进行剪枝
递归，详见代码
*/
1 /*
2 ID: Jming
3 PROG: sprime
4 LANG: C++
5 */
6 #include <iostream>
7 #include <fstream>
8 #include <sstream>
9 #include <cstdlib>
10 #include <cstdio>
11 #include <cstddef>
12 #include <iterator>
13 #include <algorithm>
14 #include <string>
15 #include <locale>
16 #include <cmath>
17 #include <vector>
18 #include <cstring>
19 #include <map>
20 #include <utility>
21 #include <queue>
22 #include <stack>
23 #include <set>
24 #include <functional>
25 using namespace std;
26 typedef pair<int, int> PII;
27 typedef long long int64;
28 const int INF = 0x3f3f3f3f;
29 const int modPrime = 3046721;
30 const double eps = 1e-9;
31 const int MaxN = 10010;
32 const int MaxM = 10010;
33
34 int N;
35
36 bool isPrime(int x)
37 {
38 if (x < 2)
39 {
40 return false;
41 }
42 for (int i = 2; i*i <= x; ++i)
43 {
44 if (x%i == 0)
45 {
46 return false;
47 }
48 }
49 return true;
50 }
51
52
53 void Solve(int val, int n)
54 {
55 if (n == N)
56 {
57 printf("%d\n", val);
58 return;
59 }
60 for (int i = 1; i <= 9; ++i)
61 {
62 int tmp = val * 10 + i;
63 // 剪枝
64 if (isPrime(tmp))
65 {
66 Solve(tmp, n + 1);
67 }
68 }
69 }
70
71 int main()
72 {
73 #ifdef HOME
74 //freopen("in", "r", stdin);
75 //freopen("out", "w", stdout);
76 #endif
77
78 freopen("sprime.in", "r", stdin);
79 freopen("sprime.out", "w", stdout);
80
81 while (~scanf("%d", &N))
82 {
83 Solve(0, 0);
84 }
85
86 #ifdef HOME
87 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
88 _CrtDumpMemoryLeaks();
89 #endif
90 return 0;
91 }
时间： 2024-10-13 11:39:26