Codeforces 777C-Alyona and Spreadsheet

本文介绍了一个关于表格排序查询的问题,需要判断给定的行区间内是否存在一列非递减排列。通过预处理每行可达的最大行数,实现了快速查询。

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Alyona and Spreadsheet
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

During the lesson small girl Alyona works with one famous spreadsheet computer program and learns how to edit tables.

Now she has a table filled with integers. The table consists of n rows and m columns. By ai, j we will denote the integer located at the i-th row and the j-th column. We say that the table is sorted in non-decreasing order in the column j if ai, j ≤ ai + 1, j for all i from 1 to n - 1.

Teacher gave Alyona k tasks. For each of the tasks two integers l and r are given and Alyona has to answer the following question: if one keeps the rows from l to r inclusive and deletes all others, will the table be sorted in non-decreasing order in at least one column? Formally, does there exist such j that ai, j ≤ ai + 1, j for all i from l to r - 1 inclusive.

Alyona is too small to deal with this task and asks you to help!

Input

The first line of the input contains two positive integers n and m (1 ≤ n·m ≤ 100 000) — the number of rows and the number of columns in the table respectively. Note that your are given a constraint that bound the product of these two integers, i.e. the number of elements in the table.

Each of the following n lines contains m integers. The j-th integers in the i of these lines stands for ai, j (1 ≤ ai, j ≤ 109).

The next line of the input contains an integer k (1 ≤ k ≤ 100 000) — the number of task that teacher gave to Alyona.

The i-th of the next k lines contains two integers li and ri (1 ≤ li ≤ ri ≤ n).

Output

Print "Yes" to the i-th line of the output if the table consisting of rows from li to ri inclusive is sorted in non-decreasing order in at least one column. Otherwise, print "No".

Example
input
5 4
1 2 3 5
3 1 3 2
4 5 2 3
5 5 3 2
4 4 3 4
6
1 1
2 5
4 5
3 5
1 3
1 5
output
Yes
No
Yes
Yes
Yes
No
Note

In the sample, the whole table is not sorted in any column. However, rows 1–3 are sorted in column 1, while rows 4–5 are sorted in column 3.


题意:给出n*m的矩阵,k次查询,如果第l行到r行至少有一列是非递减的,则输出Yes,否则输出No

解题思路:预处理每行能到达最大行是多少,把每列能到达的最大行保存一下


#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <vector>
#include <set>
#include <stack>
#include <map>
#include <climits>

using namespace std;
#define LL long long

int c[100009],d[100009];

int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m))
    {
        int a[n+10][m+10];
        for (int i=1; i<=n; i++)
            for (int j=1; j<=m; j++)
                scanf("%d",&a[i][j]);
        memset(c,0,sizeof c);
        memset(d,0,sizeof d);
        for (int i=1; i<=n; i++)
        {
            for (int j=1; j<=m; j++)
            {
                int k=max(i,d[j]);
                    while(a[k+1][j]>=a[k][j]&&k<n) k++;
                d[j]=k;
                c[i]=max(k,c[i]);
            }
        }
        int q,l,r;
        scanf("%d",&q);
        while(q--)
        {
            scanf("%d %d",&l,&r);
            if(c[l]>=r) printf("Yes\n");
            else printf("No\n");
        }
    }
    return 0;
}

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