首页 > 其他 > 详细

Palindrome Partitioning II

时间:2014-04-17 23:57:24      阅读:683      评论:0      收藏:0      [点我收藏+]

Given a string s, partition s such that every substring of the partition is a palindrome.

Return the minimum cuts needed for a palindrome partitioning of s.

For example, given s = "aab",
Return 1 since the palindrome partitioning ["aa","b"] could be produced using 1 cut.

 

这道题很惭愧,想直接在上一道题的代码上改,结果还是重写了。

之前为了方便算回文,插入“#”。但是程序会报内存不足,所以不能用这种扩展方式,只能拿string.size来建dp数组

后面根据数组,用dp继续做cut。cut的时候 cut j = min(cut j , cut i +1  (if dp[i+1][j] == 1)).要注意该推导式不需要dp[0][i] == 1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
class Solution {
public:
    int minCut(string s) {
       vector<vector <int> >dp;
        int len = s.size();
        if(len == 1)return 0;
 
        for(int i = 0 ; i < len ;i++)
        {
            vector<int> tp(len,0);
            dp.push_back(tp);
        }
        for(int i  = 0  ; i < len ; i++)
        dp[i][i] = 1;
         
        for(int i = 0  ; i < len ;i++)
        {
            int j = 1;
            while(i-j>=0 && i+j<len && s[i-j] == s[i+j])
            {
                dp[i-j][i+j] = 1;
                j++;
            }
            int x = i , y =i+1;
            while(x>=0 && y<len)
            {
                if(s[x]==s[y])
                {
                    dp[x][y]=1;
                    x--;
                    y++;
                }
                else
                break;
            }
        }
        int num = 0;
        if(dp[0][len-1]==1)return 0;
        vector<int> cut(len ,1);
        for(int i = 0 ; i < len ;i++)
        if(dp[0][i]==1)cut[i] = 1;
        else
        cut[i] = i+1;
         
        for(int i = 1;i<len;i++)
        {
            for(int j = 0 ;j <i ;j++)
            {
                 
                if(j+1<len && dp[j+1][i]==1)
                {
                    cut[i] = min(cut[j]+1,cut[i]);
                }
            }
        }
       return cut[len-1]-1;
    }
};

  

Palindrome Partitioning II,布布扣,bubuko.com

Palindrome Partitioning II

原文:http://www.cnblogs.com/pengyu2003/p/3669533.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!