1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <cmath>
 6 #include <vector>
 7
 8 using namespace std;
 9
10 #define LL long long
11 #define eps 1e-8
12 #define inf 0x3f3f3f3f
13 #define lson l, m, rt << 1
14 #define rson m+1, r, rt << 1 | 1
15 #define mnx 31000
16
17 char s[20], ch[20];
18 bool check(){
19     int n = strlen( ch );
20     for( int i = 0, j = n-1; i <= j; ++i, --j ){
21         if( ch[i] != ch[j] ) return false;
22     }
23     return true;
24 }
25 int main(){
26     scanf( "%s", &s );
27     int n = strlen( s );
28     for( int i = 0; i <= n; ++i ){
29         for( int j = 'a'; j <= 'z'; ++j ){
30             for( int k = 0, m = 0; k <= n; ++k ){
31                 if( i == k )
32                     ch[k] = (char)j;
33                 else
34                     ch[k] = s[m++];
35             }
36             ch[n+1] = '\0';
37             if( check() ){
38                 printf( "%s\n", ch );
39                 return 0;
40             }
41         }
42     }
43     puts( "NA" );
44     return 0;
45 }

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <cmath>
 6 #include <vector>
 7
 8 using namespace std;
 9
10 #define LL long long
11 #define eps 1e-8
12 #define inf 0x3f3f3f3f
13 #define lson l, m, rt << 1
14 #define rson m+1, r, rt << 1 | 1
15 #define mnx 500
16
17 int fst[mnx], nxt[mnx], vv[mnx], col[mnx], e, ans;
18 void add( int u, int v, int c ){
19     vv[e] = v, col[e] = c, nxt[e] = fst[u], fst[u] = e++;
20 }
21 bool vis[mnx], ok;
22 void dfs( int u, int gg, int vol ){
23     if( u == gg ){
24         ans++; ok = 1; return ;
25     }
26     if( vis[u] ) return ;
27     vis[u] = 1;
28     for( int i = fst[u]; i != -1; i = nxt[i] ){
29         if( ok ) return ;
30         int v = vv[i], c = col[i];
31         if( c != vol ) continue;
32         dfs( v, gg, vol );
33     }
34 }
35 int main(){
36     int n, m, q;
37     scanf( "%d %d", &n, &m );
38     memset( fst, -1, sizeof( fst ) );
39     for( int i = 0; i < m; ++i ){
40         int u, v, c;
41         scanf( "%d %d %d", &u, &v, &c );
42         add( u, v, c );
43         add( v, u, c );
44     }
45     scanf( "%d", &q );
46     while( q-- ){
47         int u, v;
48         scanf( "%d%d", &u, &v );
49         ans = 0;
50         for( int i = 1; i <= m; ++i ){
51             memset( vis, 0, sizeof( vis ) );
52             ok = 0;
53             dfs( u, v, i );
54         }
55         cout << ans << endl;
56     }
57     return 0;
58 }

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <cmath>
 6 #include <vector>
 7
 8 using namespace std;
 9
10 #define LL long long
11 #define eps 1e-8
12 #define inf 0x3f3f3f3f
13 #define lson l, m, rt << 1
14 #define rson m+1, r, rt << 1 | 1
15 #define mnx 31000
16
17 const int N = 300;
18 int dp[mnx][700], val[mnx];
19 int main(){
20     int n, m;
21     while( scanf( "%d%d", &n, &m ) != EOF ){
22         memset( val, 0, sizeof val );
23         memset( dp, 0, sizeof dp );
24         for( int i = 0; i < n; ++i ){
25             int x;
26             scanf( "%d", &x );
27             val[x]++;
28         }
29         dp[m][N] = val[m] + val[0] + 1;
30         int ans = 0;
31         for( int i = m; i < mnx; ++i ){
32             for( int j = 0; j < 600; ++j ){
33                 if( !dp[i][j] ) continue;
34                 int l = m + j - N;
35                 ans = max( dp[i][j] - 1, ans );
36                 if( i + l >= mnx ) continue;
37                 if( l > 0 )
38                     dp[i+l][j] = max( dp[i+l][j], dp[i][j] + val[i+l] );
39                 if( l > 1 )
40                     dp[i+l-1][j-1] = max( dp[i+l-1][j-1], dp[i][j] + val[i+l-1] );
41                 if( l >= 0 )
42                     dp[i+l+1][j+1] = max( dp[i+l+1][j+1], dp[i][j] + val[i+l+1] );
43             }
44         }
45         cout << ans << endl;
46     }
47     return 0;
48 }