URAL 1183 Brackets Sequence
思路:区间dp,打印路径,详见http://www.cnblogs.com/widsom/p/8321670.html
代码:
#include<iostream> #include<cstdio> #include<cstring> #include<string> #include<cmath> #include<algorithm> using namespace std; #define ll long long #define pb push_back #define mem(a,b) memset(a,b,sizeof(a)) const int N=105; int dp[N][N]; int pos[N][N]; string s; void dfs(int l,int r){ if(l>r)return ; if(l==r){ if(s[l]=='('||s[l]==')')cout<<"()"; else cout<<"[]"; } else{ if(pos[l][r]==-1){ cout<<s[l]; dfs(l+1,r-1); cout<<s[r]; } else{ dfs(l,pos[l][r]); dfs(pos[l][r]+1,r); } } } int main(){ ios::sync_with_stdio(false); cin.tie(0); cin>>s; for(int l=2;l<=s.size();l++){ for(int i=0;i+l-1<s.size();i++){ int j=i+l-1; if(s[i]=='('&&s[j]==')'||s[i]=='['&&s[j]==']')dp[i][j]=dp[i+1][j-1]+2,pos[i][j]=-1; for(int k=i;k<j;k++){ if(dp[i][k]+dp[k+1][j]>=dp[i][j]){ dp[i][j]=dp[i][k]+dp[k+1][j]; pos[i][j]=k; } } } } dfs(0,s.size()-1); return 0; }