https://codeforces.ml/contest/1440/problem/C2
This is the hard version of the problem. The difference between the versions is in the number of possible operations that can be made. You can make hacks if and only if you solved both versions of the problem.
You are given a binary table of size n×mn×m. This table consists of symbols 00 and 11.
You can make such operation: select 33 different cells that belong to one 2×22×2 square and change the symbols in these cells (change 00 to 11 and 11 to 00).
Your task is to make all symbols in the table equal to 00. You are allowed to make at most nmnm operations. You don't need to minimize the number of operations.
It can be proved, that it is always possible.
Input
The first line contains a single integer tt (1≤t≤50001≤t≤5000) — the number of test cases. The next lines contain descriptions of test cases.
The first line of the description of each test case contains two integers nn, mm (2≤n,m≤1002≤n,m≤100).
Each of the next nn lines contains a binary string of length mm, describing the symbols of the next row of the table.
It is guaranteed, that the sum of nmnm for all test cases does not exceed 2000020000.
Output
For each test case print the integer kk (0≤k≤nm0≤k≤nm) — the number of operations.
In the each of the next kk lines print 66 integers x1,y1,x2,y2,x3,y3x1,y1,x2,y2,x3,y3 (1≤x1,x2,x3≤n,1≤y1,y2,y3≤m1≤x1,x2,x3≤n,1≤y1,y2,y3≤m) describing the next operation. This operation will be made with three cells (x1,y1)(x1,y1), (x2,y2)(x2,y2), (x3,y3)(x3,y3). These three cells should be different. These three cells should belong to some 2×22×2 square.
Example
input
Copy
5 2 2 10 11 3 3 011 101 110 4 4 1111 0110 0110 1111 5 5 01011 11001 00010 11011 10000 2 3 011 101
output
Copy
1 1 1 2 1 2 2 2 2 1 3 1 3 2 1 2 1 3 2 3 4 1 1 1 2 2 2 1 3 1 4 2 3 3 2 4 1 4 2 3 3 4 3 4 4 4 1 2 2 1 2 2 1 4 1 5 2 5 4 1 4 2 5 1 4 4 4 5 3 4 2 1 3 2 2 2 3 1 2 2 1 2 2
Note
In the first test case, it is possible to make only one operation with cells (1,1)(1,1), (2,1)(2,1), (2,2)(2,2). After that, all symbols will be equal to 00.
In the second test case:
- operation with cells (2,1)(2,1), (3,1)(3,1), (3,2)(3,2). After it the table will be:
011 001 000
- operation with cells (1,2)(1,2), (1,3)(1,3), (2,3)(2,3). After it the table will be:
000 000 000
In the fifth test case:
- operation with cells (1,3)(1,3), (2,2)(2,2), (2,3)(2,3). After it the table will be:
010 110
- operation with cells (1,2)(1,2), (2,1)(2,1), (2,2)(2,2). After it the table will be:
000 000
代码:
#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn=1e6+5;
const ll mod=1e9+7;
ll t,m,n,c0,c1,h,ans,k,cnt;
char a[101][101];
ll b[maxn][10][2];
int f(int i,int j)
{
int s=0;
if(a[i][j]=='1')
s++;
if(a[i][j+1]=='1')
s++;
if(a[i+1][j]=='1')
s++;
if(a[i+1][j+1]=='1')
s++;
return s;
}
void f3(int i,int j)
{
cnt++;
int u=0;
if(a[i][j]=='1')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='0';
}
if(a[i+1][j]=='1')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='0';
}
if(a[i+1][j+1]=='1')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='0';
}
if(a[i][j+1]=='1')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='0';
}
}
void f2(int i,int j)
{
cnt++;
int u=0;
if(a[i][j]=='0')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='2';
}
if(a[i+1][j]=='0')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='2';
}
if(a[i+1][j+1]=='0')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='2';
}
if(a[i][j+1]=='0')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='2';
}
if(a[i][j]=='1')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='0';
}
else if(a[i][j]=='2')
a[i][j]='1';
if(a[i+1][j]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='0';
}
}
else if(a[i+1][j]=='2')
a[i+1][j]='1';
if(a[i+1][j+1]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='0';
}
}
else if(a[i+1][j+1]=='2')
a[i+1][j+1]='1';
if(a[i][j+1]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='0';
}
}
else if(a[i][j+1]=='2')
a[i][j+1]='1';
f3(i,j);
}
void f1(int i,int j)
{
cnt++;
int u=0;
if(a[i][j]=='0')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='2';
}
if(a[i+1][j]=='0')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='2';
}
if(a[i+1][j+1]=='0')
{
if(u==1)
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='2';
}
}
if(a[i][j+1]=='0')
{
if(u==1)
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='2';
}
}
if(a[i][j]=='1')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='0';
}
else if(a[i][j]=='2')
a[i][j]='1';
if(a[i+1][j]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='0';
}
}
else if(a[i+1][j]=='2')
a[i+1][j]='1';
if(a[i+1][j+1]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='0';
}
}
else if(a[i+1][j+1]=='2')
a[i+1][j+1]='1';
if(a[i][j+1]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='0';
}
}
else if(a[i][j+1]=='2')
a[i][j+1]='1';
f2(i,j);
}
void f4(int i,int j)
{
cnt++;
int u=0;
if(a[i][j]=='1')
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j;
a[i][j]='0';
}
if(a[i+1][j]=='1')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j;
a[i+1][j]='0';
}
if(a[i+1][j+1]=='1')
{
u++;
b[cnt][u][0]=i+1;
b[cnt][u][1]=j+1;
a[i+1][j+1]='0';
}
if(a[i][j+1]=='1')
{
if(u==2)
{
u++;
b[cnt][u][0]=i;
b[cnt][u][1]=j+1;
a[i][j+1]='0';
}
}
f1(i,j);
}
int main()
{
cin>>t;
while(t--)
{
cin>>n>>m;
for(int i=0;i<n;i++)
{
cin>>a[i];
}
cnt=0;
if(n%2&&m%2)
{
for(int j=0;j<m-1;j+=2)
{
if(a[n-1][j]=='0'&&a[n-1][j+1]=='0')
continue;
cnt++;
int u=0;
if(a[n-1][j]=='1')
{
u++;
b[cnt][u][0]=n-1;
b[cnt][u][1]=j;
a[n-1][j]='0';
}
if(a[n-1][j+1]=='1')
{
u++;
b[cnt][u][0]=n-1;
b[cnt][u][1]=j+1;
a[n-1][j+1]='0';
}
if(u==1)
{
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j;
if(a[n-2][j]=='1')
a[n-2][j]='0';
else
a[n-2][j]='1';
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j+1;
if(a[n-2][j+1]=='1')
a[n-2][j+1]='0';
else
a[n-2][j+1]='1';
}
else if(u==2)
{
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j;
if(a[n-2][j]=='1')
a[n-2][j]='0';
else
a[n-2][j]='1';
}
}
for(int j=0;j<n-1;j+=2)
{
if(a[j][m-1]=='0'&&a[j+1][m-1]=='0')
continue;
cnt++;
int u=0;
if(a[j][m-1]=='1')
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-1;
a[j][m-1]='0';
}
if(a[j+1][m-1]=='1')
{
u++;
b[cnt][u][0]=j+1;
b[cnt][u][1]=m-1;
a[j+1][m-1]='0';
}
if(u==1)
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-2;
if(a[j][m-2]=='1')
a[j][m-2]='0';
else
a[j][m-2]='1';
u++;
b[cnt][u][0]=j+1;
b[cnt][u][1]=m-2;
if(a[j+1][m-2]=='1')
a[j+1][m-2]='0';
else
a[j+1][m-2]='1';
}
else if(u==2)
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-2;
if(a[j][m-2]=='1')
a[j][m-2]='0';
else
a[j][m-2]='1';
}
}
if(a[n-1][m-1]=='1')
{
cnt++;
b[cnt][1][0]=n-1;
b[cnt][1][1]=m-1;
b[cnt][2][0]=n-2;
b[cnt][2][1]=m-1;
b[cnt][3][0]=n-1;
b[cnt][3][1]=m-2;
cnt++;
b[cnt][1][0]=n-2;
b[cnt][1][1]=m-2;
b[cnt][2][0]=n-2;
b[cnt][2][1]=m-1;
b[cnt][3][0]=n-1;
b[cnt][3][1]=m-2;
if(a[n-2][m-2]=='0')
a[n-2][m-2]='1';
else
a[n-2][m-2]='0';
a[n-1][m-1]='0';
}
}
else if(n%2)
{
for(int j=0;j<m-1;j+=2)
{
if(a[n-1][j]=='0'&&a[n-1][j+1]=='0')
continue;
cnt++;
int u=0;
if(a[n-1][j]=='1')
{
u++;
b[cnt][u][0]=n-1;
b[cnt][u][1]=j;
a[n-1][j]='0';
}
if(a[n-1][j+1]=='1')
{
u++;
b[cnt][u][0]=n-1;
b[cnt][u][1]=j+1;
a[n-1][j+1]='0';
}
if(u==1)
{
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j;
if(a[n-2][j]=='1')
a[n-2][j]='0';
else
a[n-2][j]='1';
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j+1;
if(a[n-2][j+1]=='1')
a[n-2][j+1]='0';
else
a[n-2][j+1]='1';
}
else if(u==2)
{
u++;
b[cnt][u][0]=n-2;
b[cnt][u][1]=j;
if(a[n-2][j]=='1')
a[n-2][j]='0';
else
a[n-2][j]='1';
}
}
}
else if(m%2)
{
for(int j=0;j<n-1;j+=2)
{
if(a[j][m-1]=='0'&&a[j+1][m-1]=='0')
continue;
cnt++;
int u=0;
if(a[j][m-1]=='1')
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-1;
a[j][m-1]='0';
}
if(a[j+1][m-1]=='1')
{
u++;
b[cnt][u][0]=j+1;
b[cnt][u][1]=m-1;
a[j+1][m-1]='0';
}
if(u==1)
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-2;
if(a[j][m-2]=='1')
a[j][m-2]='0';
else
a[j][m-2]='1';
u++;
b[cnt][u][0]=j+1;
b[cnt][u][1]=m-2;
if(a[j+1][m-2]=='1')
a[j+1][m-2]='0';
else
a[j+1][m-2]='1';
}
else if(u==2)
{
u++;
b[cnt][u][0]=j;
b[cnt][u][1]=m-2;
if(a[j][m-2]=='1')
a[j][m-2]='0';
else
a[j][m-2]='1';
}
}
}
for(int i=0;i<n-1;i+=2)
{
for(int j=0;j<m-1;j+=2)
{
if(f(i,j)==0)
continue;
else if(f(i,j)==3)
{
f3(i,j);
}
else if(f(i,j)==2)
{
f2(i,j);
}
else if(f(i,j)==4)
{
f4(i,j);
}
else
{
f1(i,j);
}
}
}
cout<<cnt<<endl;
for(int i=1;i<=cnt;i++)
{
for(int j=1;j<=3;j++)
{
cout<<b[i][j][0]+1<<" "<<b[i][j][1]+1;
if(j==3)
{
if(i==cnt)
cout<<endl;
else
cout<<" \n";
}
else
cout<<" ";
}
}
}
return 0;
}

在给定的二进制矩阵中,通过选取不同位置的3个相邻单元格进行符号翻转,使得所有元素变为0。题目提供了最大操作次数,并保证解决方案总是存在的。给出输入输出示例以及操作描述。
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