POJ 1068
Parencodings
Time Limit: 1000MS | Memory Limit: 10000K |
Total Submissions: 28491 | Accepted: 16786 |
Description
Let S = s1 s2...s2n be a well-formed string of parentheses. S can be encoded in two different ways: q By an integer sequence P = p1 p2...pn where pi is the number of left parentheses before the ith right parenthesis in S (P-sequence). q By an integer sequence W = w1 w2...wn where for each right parenthesis, say a in S, we associate an integer which is the number of right parentheses counting from the matched left parenthesis of a up to a. (W-sequence). Following is an example of the above encodings:
S (((()()()))) P-sequence 4 5 6666 W-sequence 1 1 1456
Write a program to convert P-sequence of a well-formed string to the W-sequence of the same string.
Input
The first line of the input contains a single integer t (1 <= t <= 10), the number of test cases, followed by the input data for each test case. The first line of each test case is an integer n (1 <= n <= 20), and the second line is the P-sequence of a well-formed string. It contains n positive integers, separated with blanks, representing the P-sequence.
Output
The output file consists of exactly t lines corresponding to test cases. For each test case, the output line should contain n integers describing the W-sequence of the string corresponding to its given P-sequence.
Sample Input
2 6 4 5 6 6 6 6 9 4 6 6 6 6 8 9 9 9
Sample Output
1 1 1 4 5 6 1 1 2 4 5 1 1 3 9
Source
大致題意:
一個括號表示式可以按照如下的規則表示,就是每個右括號之前的左括號數。
比如(((()()()))),每個右括號之前的左括號數序列為P=4 5 6 6 6 6,而每個右括號所在的括號內包含的括號數為W=1 1 1 4 5 6.
現在給定P,輸出W。
解題思路:
先根據P還原整個括號表示式,存在陣列中,然後遞迴解出W..
程式碼:
#include<iostream>
using namespace std;
char y[10000]; int p[50],w[50],n,l,j; //y為還原後的括號
int f()
{
int s=1; //消除之前的連續左括號對結果的影響
while(1)
if(y[j]=='(') //若是左括號,繼續遞迴求解
{
j++;
s+=f();
}
else //若是右括號,將已有括號數寫入W
{
w[l++]=s;
j++;
return s;
}
}
int main()
{
int t,i,k;
cin>>t; //例子個數
while(t--)
{
cin>>n; //右括號個數
for(i=0,l=0,k=0;i<n;i++)
{
cin>>p[i]; //輸入P
for(j=0;j<p[i]-k;j++) //每個右括號前的左括號加入序列
y[l++]='(';
y[l++]=')'; //加入此次右括號
k=p[i]; //之前加過的左括號去掉,以免重複
}
l=j=0;
f();
for(i=0;i<n;i++)
cout<<w[i]<<' ';
cout<<endl;
}
return 0;
}