Codeforces Round #238 (Div. 2)

500pt:

题目链接：http://codeforces.com/problemset/problem/405/A

A. Gravity Flip

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Little Chris is bored during his physics lessons (too easy), so he has built a toy box to keep himself occupied. The box is special, since it has the ability to change gravity.

There are n columns of toy cubes in the box arranged in a line. The i-th column contains ai cubes. At first, the gravity in the box is pulling the cubes downwards. When Chris switches the gravity, it begins to pull all the cubes to the right side of the box. The figure shows the initial and final configurations of the cubes in the box: the cubes that have changed their position are highlighted with orange.

Given the initial configuration of the toy cubes in the box, find the amounts of cubes in each of the n columns after the gravity switch!

Input

The first line of input contains an integer n (1 ≤ n ≤ 100), the number of the columns in the box. The next line contains n space-separated integer numbers. The i-th number ai (1 ≤ ai ≤ 100) denotes the number of cubes in the i-th column.

Output

Output n integer numbers separated by spaces, where the i-th number is the amount of cubes in the i-th column after the gravity switch.

Sample test(s)

input

4
3 2 1 2

output

1 2 2 3 

input

3
2 3 8

output

2 3 8 

Note

The first example case is shown on the figure. The top cube of the first column falls to the top of the last column; the top cube of the second column falls to the top of the third column; the middle cube of the first column falls to the top of the second column.

In the second example case the gravity switch does not change the heights of the columns.

题目分析：就是一个排序。。。。

代码：

#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <string>
#include <string.h>
using namespace std;
typedef long long ll;
const int N=100010;
int arr[N];
int n;
int main()
{
    while(cin>>n)
    {
        for(int i=0;i<n;i++)
            cin>>arr[i];
        sort(arr,arr+n);
        for(int i=0;i<n;i++)
            cout<<arr[i]<<" ";
        cout<<endl;
    }
    return 0;
}

1000pt:

题目链接：http://codeforces.com/problemset/problem/405/B

B. Domino Effect

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Little Chris knows there's no fun in playing dominoes, he thinks it's too random and doesn't require skill. Instead, he decided to play withthe dominoes and make a "domino show".

Chris arranges n dominoes in a line, placing each piece vertically upright. In the beginning, he simultaneously pushes some of the dominoes either to the left or to the right. However, somewhere between every two dominoes pushed in the same direction there is at least one domino pushed in the opposite direction.

After each second, each domino that is falling to the left pushes the adjacent domino on the left. Similarly, the dominoes falling to the right push their adjacent dominoes standing on the right. When a vertical domino has dominoes falling on it from both sides, it stays still due to the balance of the forces. The figure shows one possible example of the process.

Given the initial directions Chris has pushed the dominoes, find the number of the dominoes left standing vertically at the end of the process!

Input

The first line contains a single integer n (1 ≤ n ≤ 3000), the number of the dominoes in the line. The next line contains a character strings of length n. The i-th character of the string si is equal to

• "L", if the i-th domino has been pushed to the left;
• "R", if the i-th domino has been pushed to the right;
• ".", if the i-th domino has not been pushed.

It is guaranteed that if si = sj = "L" and i < j, then there exists such k that i < k < j and sk = "R"; if si = sj = "R" and i < j, then there exists such k that i < k < j and sk = "L".

Output

Output a single integer, the number of the dominoes that remain vertical at the end of the process.

Sample test(s)

input

14
.L.R...LR..L..

output

4

input

5
R....

output

0

input

1
.

output

1

Note

The first example case is shown on the figure. The four pieces that remain standing vertically are highlighted with orange.

In the second example case, all pieces fall down since the first piece topples all the other pieces.

In the last example case, a single piece has not been pushed in either direction.

分析：字符串题，注意只有可能先R再L中间才有可能有一个竖直的，保存前一个状态，然后处理当前状态即可。

代码：

#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <string>
#include <string.h>
using namespace std;
typedef long long ll;
const int N=100010;
char arr[N];
int n;
int main()
{
    cin>>n;
    for(int i=0;i<n;i++)
        cin>>arr[i];
    int ret = 0;
    char pre = '?';
    int preIndex = -1;
    int i=0;
    while(i<n)
    {
        if(arr[i]=='.')
        {
            i++;
        }
        else if(arr[i]=='L')
        {
            if(pre=='R')
            {
                if((i-preIndex)%2==0)
                    ret++;
                pre = '?';
                preIndex=i;
            }
            else
            {
                pre = 'L';
                preIndex = i;
            }
            i++;
        }
        else
        {
            if(pre=='L'||pre=='?')
            {
                ret+=i-preIndex-1;
                pre = 'R';
                preIndex = i;
            }
            else if(pre=='R')
            {
                preIndex = i;
            }
            i++;
        }
    }
    if(pre!='R')
    {
        ret+=n-preIndex-1;
    }
    cout<<ret<<endl;

    return 0;
}

1500pt:

题目链接：http://codeforces.com/problemset/problem/405/C

C. Unusual Product

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Little Chris is a huge fan of linear algebra. This time he has been given a homework about the unusual square of a square matrix.

The dot product of two integer number vectors x and y of size n is the sum of the products of the corresponding components of the vectors. The unusual square of an n × n square matrix A is defined as the sum of n dot products. The i-th of them is the dot product of the i-th row vector and the i-th column vector in the matrix A.

Fortunately for Chris, he has to work only in GF(2)! This means that all operations (addition, multiplication) are calculated modulo 2. In fact, the matrix A is binary: each element of A is either 0 or 1. For example, consider the following matrix A:

The unusual square of A is equal to (1·1 + 1·0 + 1·1) + (0·1 + 1·1 + 1·0) + (1·1 + 0·1 + 0·0) = 0 + 1 + 1 = 0.

However, there is much more to the homework. Chris has to process q queries; each query can be one of the following:

1. given a row index i, flip all the values in the i-th row in A;
2. given a column index i, flip all the values in the i-th column in A;
3. find the unusual square of A.

To flip a bit value w means to change it to 1 - w, i.e., 1 changes to 0 and 0 changes to 1.

Given the initial matrix A, output the answers for each query of the third type! Can you solve Chris's homework?

Input

The first line of input contains an integer n (1 ≤ n ≤ 1000), the number of rows and the number of columns in the matrix A. The next nlines describe the matrix: the i-th line contains n space-separated bits and describes the i-th row of A. The j-th number of the i-th lineaij (0 ≤ aij ≤ 1) is the element on the intersection of the i-th row and the j-th column of A.

The next line of input contains an integer q (1 ≤ q ≤ 106), the number of queries. Each of the next q lines describes a single query, which can be one of the following:

• 1 i — flip the values of the i-th row;
• 2 i — flip the values of the i-th column;
• 3 — output the unusual square of A.

Note: since the size of the input and output could be very large, don't use slow output techniques in your language. For example, do not use input and output streams (cin, cout) in C++.

Output

Let the number of the 3rd type queries in the input be m. Output a single string s of length m, where the i-th symbol of s is the value of the unusual square of A for the i-th query of the 3rd type as it appears in the input.

Sample test(s)

input

3
1 1 1
0 1 1
1 0 0
12
3
2 3
3
2 2
2 2
1 3
3
3
1 2
2 1
1 1
3

output

01001

分析：猜的结论：type 2和3每次都会使结果相反，0变1,1变0

代码：

#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <string>
#include <string.h>
using namespace std;
typedef long long ll;
const int N=1010;
int arr[N][N];
int n;
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			scanf("%d",&arr[i][j]);
	int total = 0;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			total^=(arr[i][j]&arr[j][i]);
		}
	}
	int q;
	cin>>q;
	string ret = "";
	while(q--)
	{
		int type;
		cin>>type;
		if(type==3)
		{
			if(total)
				ret+="1";
			else
				ret+="0";
		}
		else 
		{
			int c;
			cin>>c;
			total^=1;
		}
	}
	cout<<ret<<endl;
	return 0;
}