hdoj - 5202 Rikka with string (BestCoder Round #37 ($))

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 #include <vector>
 5 #include <cstring>
 6 #include <string>
 7 #include <algorithm>
 8 #include <string>
 9 #include <set>
10 #include <functional>
11 #include <numeric>
12 #include <sstream>
13 #include <stack>
14 #include <map>
15 #include <queue>
16 
17 #define CL(arr, val)    memset(arr, val, sizeof(arr))
18 
19 #define ll long long
20 #define inf 0x7f7f7f7f
21 #define lc l,m,rt<<1
22 #define rc m + 1,r,rt<<1|1
23 #define pi acos(-1.0)
24 
25 #define L(x)    (x) << 1
26 #define R(x)    (x) << 1 | 1
27 #define MID(l, r)   (l + r) >> 1
28 #define Min(x, y)   (x) < (y) ? (x) : (y)
29 #define Max(x, y)   (x) < (y) ? (y) : (x)
30 #define E(x)        (1 << (x))
31 #define iabs(x)     (x) < 0 ? -(x) : (x)
32 #define OUT(x)  printf("%I64d\n", x)
33 #define lowbit(x)   (x)&(-x)
34 #define Read()  freopen("a.txt", "r", stdin)
35 #define Write() freopen("dout.txt", "w", stdout);
36 #define N 100005
37 using namespace std;
38 
39 bool palindrome(char *str)  
40 {
41     int len=strlen(str);
42     for(int i=0;i<len/2;i++)
43     {
44         if(str[i]!=str[len-i-1]) return 0;
45     }
46     return 1;
47 }
48 char s[1010];
49 int f[1010];
50 int main()
51 {
52    //Read();
53     int n;
54     while(scanf("%d",&n)!=EOF)
55     {
56         getchar();
57         gets(s);
58         //printf("%s\n",s);
59         bool flag=0;
60         for(int i=0;i<strlen(s);i++)
61         {
62             if(!((s[i]>=‘a‘&&s[i]<=‘z‘)||s[i]==‘?‘))  {flag=1;break;}
63         }
64         //printf("%d\n",flag);
65         if(flag) {printf("QwQ\n");continue;}
66         for(int i=0;i<strlen(s);i++)
67         {
68             if(s[i]==‘?‘) {flag=1;break;}
69         }
70         if(!flag&&palindrome(s)) {printf("QwQ\n");continue;}
71         int j=0;
72         memset(f,0,sizeof(f));
73         for(int i=0;i<strlen(s);i++)
74         {
75             if(s[i]==‘?‘)
76             {
77                 s[i]=‘a‘;
78                 f[j++]=i;
79             }
80         }
81         j--;
82         flag=0;
83         if(palindrome(s))
84         {
85             s[f[j]]=‘b‘;   //从后往前替换  注意 a??aa
86             while(palindrome(s))
87             {
88                 if(j==0) {flag=1;break;}
89                 j--;
90                 s[f[j]]=‘b‘;
91                 s[f[j+1]]=‘a‘;
92             }
93         }
94         if(flag) printf("QwQ\n");
95         else
96         printf("%s\n",s);
97     }
98     return 0;
99 }