poj1363 Rails Central Europe 1997
作者：互联网
P.S.:
输出换行
三个方法
1.直接按照要求做
根据给的数，需要push,pop哪些数据，具有唯一性
数最多加栈一次，出栈一次
O(n)
1 Source Code
2 Problem: 1363 User: congmingyige
3 Memory: 728K Time: 63MS
4 Language: G++ Result: Accepted
5
6 Source Code
7
8 #include <cstdio>
9 #include <cstdlib>
10 #include <cmath>
11 #include <cstring>
12 #include <string>
13 #include <algorithm>
14 #include <iostream>
15 using namespace std;
16 #define ll long long
17
18 const double eps=1e-8;
19 const ll inf=1e9;
20 const ll mod=1e9+7;
21 const int maxn=1e5+10;
22
23 int a[maxn];
24 int st[maxn];
25
26 int main()
27 {
28 int n,i,j,g;
29 bool line=0;
30 while (1)
31 {
32 scanf("%d",&n);
33 if (n==0)
34 break;
35
36 if (!line)
37 line=1;
38 else
39 printf("\n");
40
41 g=0;
42 while (1)
43 {
44 scanf("%d",&a[1]);
45 if (a[1]==0)
46 break;
47 for (i=2;i<=n;i++)
48 scanf("%d",&a[i]);
49
50 j=0;
51 for (i=1;i<=n;i++)
52 {
53 while (j<a[i])
54 st[++g]=++j;
55 if (st[g]==a[i])
56 g--;
57 else
58 break;
59 }
60
61 if (i==n+1)
62 printf("Yes\n");
63 else
64 printf("No\n");
65 }
66 }
67 return 0;
68 }
69 /*
70 6
71 1 3 2 4 6 5
72 1 4 3 5 2 6
73 1 3 6 5 2 4
74 5 4 3 2 1 6
75 5 3 2 1 6 4
76 1 3 5 4 6 2
77 1 3 6 2 5 4
78
79 4
80 1 2 3 4
81 1 2 4 3
82 1 3 2 4
83 1 3 4 2
84 1 4 2 3
85 1 4 3 2
86 2 1 3 4
87 2 1 4 3
88 2 3 1 4
89 2 3 4 1
90 2 4 1 3
91 2 4 3 1
92 3 1 2 4
93 3 1 4 2
94 3 2 1 4
95 3 2 4 1
96 3 4 1 2
97 3 4 2 1
98 4 1 2 3
99 4 1 3 2
100 4 2 1 3
101 4 2 3 1
102 4 3 1 2
103 4 3 2 1
104
105 2 3 1 4
106 */
2.
一个序列，数x在第y个位置，第y个位置之后的小于x的数，必须是越往右越小。 即当前的最大数假设为z，则小于z的数必须是z-1,z-2,..,1。时间上为O(n)，但常数较大
1 #include <cstdio>
2 #include <cstdlib>
3 #include <cmath>
4 #include <cstring>
5 #include <string>
6 #include <algorithm>
7 #include <iostream>
8 using namespace std;
9 #define ll long long
10
11 const double eps=1e-8;
12 const ll inf=1e9;
13 const ll mod=1e9+7;
14 const int maxn=1e5+10;
15
16 int a[maxn];
17 bool vis[maxn];
18
19 int main()
20 {
21 int n,i,j;
22 bool line=0;
23 while (1)
24 {
25 scanf("%d",&n);
26 if (n==0)
27 break;
28
29 if (!line)
30 line=1;
31 else
32 printf("\n");
33
34 while (1)
35 {
36 scanf("%d",&a[1]);
37 if (a[1]==0)
38 break;
39 for (i=2;i<=n;i++)
40 scanf("%d",&a[i]);
41
42 memset(vis,0,sizeof(vis));
43 j=0;
44 for (i=1;i<=n;i++)
45 {
46 if (j>a[i])
47 break;
48 else if (j<=a[i])
49 j=a[i]-1;
50
51 vis[a[i]]=1;
52 while (vis[j])
53 j--;
54 }
55
56 if (i==n+1)
57 printf("Yes\n");
58 else
59 printf("No\n");
60 }
61 }
62 return 0;
63 }
64 /*
65 6
66 1 3 2 4 6 5
67 1 4 3 5 2 6
68 1 3 6 5 2 4
69 5 4 3 2 1 6
70 5 3 2 1 6 4
71 1 3 5 4 6 2
72 1 3 6 2 5 4
73
74 8
75 1 3 6 8 7 5 4 2
76
77 4
78 1 2 3 4
79 1 2 4 3
80 1 3 2 4
81 1 3 4 2
82 1 4 2 3
83 1 4 3 2
84 2 1 3 4
85 2 1 4 3
86 2 3 1 4
87 2 3 4 1
88 2 4 1 3
89 2 4 3 1
90 3 1 2 4
91 3 1 4 2
92 3 2 1 4
93 3 2 4 1
94 3 4 1 2
95 3 4 2 1
96 4 1 2 3
97 4 1 3 2
98 4 2 1 3
99 4 2 3 1
100 4 3 1 2
101 4 3 2 1
102
103 2 3 1 4
104 */
previous数组
一个数跳出，使用previous数组，这个数不再被使用
O(n)
1 3 2 6 5 4 9 8 7
则
previous[4] 0
previous[6] 6->5->4->0 0
previous[7] 7->6->0
极限数据
1 2 3 4 5 6 7 8 9
按照上述方法O(n^2)
1 #include <cstdio>
2 #include <cstdlib>
3 #include <cmath>
4 #include <cstring>
5 #include <string>
6 #include <algorithm>
7 #include <iostream>
8 using namespace std;
9 #define ll long long
10
11 const double eps=1e-8;
12 const ll inf=1e9;
13 const ll mod=1e9+7;
14 const int maxn=1e5+10;
15
16 int a[maxn],pre[maxn];
17 bool vis[maxn];
18
19 int main()
20 {
21 int n,i,j,k;
22 bool line=0;
23 while (1)
24 {
25 scanf("%d",&n);
26 if (n==0)
27 break;
28
29 if (!line)
30 line=1;
31 else
32 printf("\n");
33
34 while (1)
35 {
36 scanf("%d",&a[1]);
37 if (a[1]==0)
38 break;
39 for (i=2;i<=n;i++)
40 scanf("%d",&a[i]);
41
42 memset(vis,0,sizeof(vis));
43 j=0;
44 for (i=1;i<=n;i++)
45 {
46 if (j>a[i])
47 break;
48 else if (j<=a[i])
49 j=a[i]-1,k=j;
50
51 vis[a[i]]=1;
52 while (vis[j])
53 {
54 if (pre[j])
55 j=pre[j];
56 else
57 j--;
58 }
59 if (j!=k)
60 pre[k]=j;
61 }
62
63 if (i==n+1)
64 printf("Yes\n");
65 else
66 printf("No\n");
67 }
68 }
69 return 0;
70 }
71 /*
72 6
73 1 3 2 4 6 5
74 1 4 3 5 2 6
75 1 3 6 5 2 4
76 5 4 3 2 1 6
77 5 3 2 1 6 4
78 1 3 5 4 6 2
79 1 3 6 2 5 4
80
81 8
82 1 3 6 8 7 5 4 2
83
84 4
85 1 2 3 4
86 1 2 4 3
87 1 3 2 4
88 1 3 4 2
89 1 4 2 3
90 1 4 3 2
91 2 1 3 4
92 2 1 4 3
93 2 3 1 4
94 2 3 4 1
95 2 4 1 3
96 2 4 3 1
97 3 1 2 4
98 3 1 4 2
99 3 2 1 4
100 3 2 4 1
101 3 4 1 2
102 3 4 2 1
103 4 1 2 3
104 4 1 3 2
105 4 2 1 3
106 4 2 3 1
107 4 3 1 2
108 4 3 2 1
109
110 2 3 1 4
111 */
标签：Europe,Central,1997,int,ll,maxn,const,line,include 来源： https://www.cnblogs.com/cmyg/p/11110541.html