poj1141 区间dp+路径

  1 //Accepted    176 KB    47 ms
  2 //感谢大神们为我们这群渣渣铺平前进的道路！！
  3 //用scanf("%s",s)!=EOF  WA到死
  4 #include <cstdio>
  5 #include <cstring>
  6 #include <iostream>
  7 using namespace std;
  8 const int imax_n = 105;
  9 const int inf = 100000000;
 10 char s[imax_n];
 11 int dp[imax_n][imax_n];
 12 int n;
 13 int min(int a,int b)
 14 {
 15     return a<b?a:b;
 16 }
 17 int isMatch(char ch1,char ch2)
 18 {
 19     if (ch1==‘(‘ && ch2==‘)‘) return 1;
 20     if (ch1==‘[‘ && ch2==‘]‘) return 1;
 21     return 0;
 22 }
 23 void Dp()
 24 {
 25     memset(dp,0,sizeof(dp));
 26     for (int i=1;i<=n;i++)
 27     {
 28         dp[i][i]=1;
 29     }
 30     for (int i=1;i<n;i++)
 31     {
 32         if (isMatch(s[i-1],s[i])) dp[i][i+1]=0;
 33         else
 34         dp[i][i+1]=2;
 35     }
 36     for (int l=3;l<=n;l++)
 37     {
 38         for (int i=1;i<=n;i++)
 39         {
 40             int j=i+l-1;
 41             if (j>n) break;
 42             dp[i][j]=inf;
 43             if (isMatch(s[i-1],s[j-1])) dp[i][j]=dp[i+1][j-1];
 44             if (s[i-1]==‘(‘ || s[i-1]==‘[‘) dp[i][j]=min(dp[i][j],dp[i+1][j]+1);
 45             if (s[j-1]==‘)‘ || s[j-1]==‘]‘) dp[i][j]=min(dp[i][j],dp[i][j-1]+1);
 46             for (int k=i;k<j;k++)
 47             dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]);
 48         }
 49     }
 50 }
 51 void output(int i,int j)
 52 {
 53     //printf("s[%d]=%c,s[%d]=%c\n",i,s[i-1],j,s[j-1]);
 54     if (i>j) return ;
 55     if (dp[i][j]==0)
 56     {
 57         for (int k=i;k<=j;k++)
 58         printf("%c",s[k-1]);
 59         return ;
 60     }
 61     if (dp[i][j]==1 && i==j)
 62     {
 63         if (s[i-1]==‘(‘ || s[i-1]==‘)‘)
 64         printf("()");
 65         if (s[i-1]==‘[‘ || s[i-1]==‘]‘)
 66         printf("[]");
 67         return ;
 68     }
 69     if (dp[i][j]==dp[i+1][j-1] && isMatch(s[i-1],s[j-1]))
 70     {
 71         printf("%c",s[i-1]);
 72         output(i+1,j-1);
 73         printf("%c",s[j-1]);
 74         return ;
 75     }
 76     if (dp[i][j]==dp[i+1][j]+1 && (s[i-1]==‘(‘ || s[i-1]==‘[‘))
 77     {
 78         printf("%c",s[i-1]);
 79         output(i+1,j);
 80         if (s[i-1]==‘(‘)
 81         printf(")");
 82         else
 83         printf("]");
 84         return ;
 85     }
 86     if (dp[i][j]==dp[i][j-1]+1 && (s[j-1]==‘)‘ || s[j-1]==‘]‘))
 87     {
 88         if (s[j-1]==‘)‘)
 89         printf("(");
 90         else
 91         printf("[");
 92         output(i,j-1);
 93         printf("%c",s[j-1]);
 94         return ;
 95     }
 96     for (int k=i;k<j;k++)
 97     if (dp[i][j]==dp[i][k]+dp[k+1][j])
 98     {
 99         output(i,k);
100         output(k+1,j);
101         return ;
102     }
103     return ;
104 }
105 int main()
106 {
107     //while (cin>>s)
108     {
109         scanf("%s",s);
110         n=strlen(s);
111         Dp();
112         output(1,n);
113         printf("\n");
114     }
115     return 0;
116 }