【HDOJ】4628 Pieces

最开始的想法是搜索,发现不对,后来发现数据量很小,可以状态压缩+DP。

 1 /* 4628 */
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5
 6 #define MAXN 17
 7 #define INF    9999
 8
 9 char s[MAXN];
10 char ss[MAXN];
11 int dp[1<<MAXN];
12 int len;
13
14 inline int max(int a, int b) {
15     return a>b ? a:b;
16 }
17
18 inline int min(int a, int b) {
19     return a<b ? a:b;
20 }
21
22 bool isPalindrome(int x) {
23     int i, j, l = 0;
24
25     for (i=0, j=1; i<len; ++i, j<<=1)
26         if (x & j)
27             ss[l++] = s[i];
28
29     i = 0;
30     j = l-1;
31     while (i<=j && ss[i]==ss[j])
32         ++i, --j;
33     if (i > j)
34         return true;
35     else
36         return false;
37 }
38
39 int main() {
40     int t;
41     int i, j, k;
42
43     #ifndef ONLINE_JUDGE
44         freopen("data.in", "r", stdin);
45     #endif
46
47     scanf("%d", &t);
48     while (t--) {
49         scanf("%s", s);
50         len = strlen(s);
51         for (i=1; i<(1<<len); ++i) {
52             dp[i] = INF;
53             if (isPalindrome(i))
54                 dp[i] = 1;
55             else {
56                 for (j=i; j; j=(j-1)&i)
57                     dp[i] = min(dp[i], dp[j]+dp[i^j]);
58             }
59         }
60         printf("%d\n", dp[(1<<len)-1]);
61     }
62
63     return 0;
64 }
时间: 2024-10-11 22:51:24

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