time limit per test2 seconds
memory limit per test256 megabytes
inputstandard input
outputstandard output
Mike and some bears are playing a game just for fun. Mike is the judge. All bears except Mike are standing in an n × m grid, there’s exactly one bear in each cell. We denote the bear standing in column number j of row number i by (i, j). Mike’s hands are on his ears (since he’s the judge) and each bear standing in the grid has hands either on his mouth or his eyes.
They play for q rounds. In each round, Mike chooses a bear (i, j) and tells him to change his state i. e. if his hands are on his mouth, then he’ll put his hands on his eyes or he’ll put his hands on his mouth otherwise. After that, Mike wants to know the score of the bears.
Score of the bears is the maximum over all rows of number of consecutive bears with hands on their eyes in that row.
Since bears are lazy, Mike asked you for help. For each round, tell him the score of these bears after changing the state of a bear selected in that round.
Input
The first line of input contains three integers n, m and q (1 ≤ n, m ≤ 500 and 1 ≤ q ≤ 5000).
The next n lines contain the grid description. There are m integers separated by spaces in each line. Each of these numbers is either 0 (for mouth) or 1 (for eyes).
The next q lines contain the information about the rounds. Each of them contains two integers i and j (1 ≤ i ≤ n and 1 ≤ j ≤ m), the row number and the column number of the bear changing his state.
Output
After each round, print the current score of the bears.
Sample test(s)
input
5 4 5
0 1 1 0
1 0 0 1
0 1 1 0
1 0 0 1
0 0 0 0
1 1
1 4
1 1
4 2
4 3
output
3
4
3
3
4
这道题的意思是给你一个由1和0组成的n*m的矩形，后面再输入坐标，坐标相对应的数字要反转，1变为0,0变为1，然后输出每次变化后每行1的最大连续值。
#include<iostream>
#include<string.h>
using namespace std;
int a[510][510];
int big[510];
int main()
{
int n,m,t;
while(cin>>n>>m>>t)
{
int sum=0;
for(int i=1;i<=n;i++)
{
sum=0;
for(int j=1;j<=m;j++)
{
cin>>a[i][j];
if(a[i][j]==1) sum+=a[i][j];
else
{
big[i]=big[i]>sum?big[i]:sum;
sum=0;
}
}
big[i]=big[i]>sum?big[i]:sum; //求出每行1的最大连续值
}
for(int i=0;i<t;i++)
{
int ans,nut;
cin>>ans>>nut;
if(a[ans][nut]==1) a[ans][nut]=0;
else a[ans][nut]=1;
sum=0;
int max=0;
for(int k=1;k<=m;k++)
{
if(a[ans][k]==1) sum+=a[ans][k];
else
{
max=max>sum?max:sum;
sum=0;
}
}
max=max>sum?max:sum; //变化后的最大连续值
big[ans]=max;
max=0;
for(int k=1;k<=n;k++) max=max>big[k]?max:big[k]; //在整个矩阵中比较每行的最大值
cout<<max<<endl;
}
}
return 0;
}