Here are two solutions to problem D of today's contest↵
↵
1.First solution-->↵
↵
<spoiler summary="My Code1">↵
```c++↵
↵
#include <bits/stdc++.h>↵
using namespace std;↵
↵
void init_code(){↵
#ifndef ONLINE_JUDGE↵
freopen("input.txt", "r", stdin);↵
freopen("output.txt", "w", stdout);↵
#endif↵
}↵
↵
↵
↵
int main() {↵
init_code();↵
// read(T);↵
int T;↵
cin>>T;↵
while(T--){↵
int n,ans = 0;↵
cin>>n;↵
vector<string>v(n);↵
for(auto&i:v){↵
cin>>i;↵
}↵
vector<vector<int>>left(n,vector<int>(n)), right(n,vector<int>(n)), down(n, vector<int>(n));↵
for(int i = 0;i<n;i++){↵
for(int j = 0;j<n;j++){↵
int x = v[i][j] - '0';↵
if(left[i][j]){↵
x^=1;↵
if(i + 1 < n){↵
if(j - 1>=0){↵
left[i + 1][j - 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
↵
}↵
}↵
if(down[i][j]){↵
x^=1;↵
if(i + 1 <n){↵
down[i + 1][j]^=1;↵
}↵
}↵
if(right[i][j]){↵
x^=1;↵
if(i + 1 < n){↵
if(j + 1 < n){↵
right[i + 1][j + 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
}↵
}↵
↵
if(x){↵
ans++;↵
if(i + 1 < n){↵
if(j - 1 >= 0){↵
left[i + 1][j - 1]^=1;↵
}↵
if(j + 1<n){↵
right[i + 1][j + 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
}↵
↵
}↵
↵
}↵
↵
}↵
cout<<ans<<endl;↵
}↵
}↵
```↵
</spoiler>↵
↵
2. Second solution↵
↵
<spoiler summary="His Code">↵
```c++↵
↵
#include <bits/stdc++.h>↵
#define int long long↵
using namespace std;↵
const int mod = 998244353;↵
template <typename T>↵
istream &operator>>(istream &istream, vector<T> &v){for (auto &it : v) cin >> it; return istream;}↵
template <typename T>↵
ostream &operator<<(ostream &ostream, vector<T> &v){for (auto &it : v) cout << it << ' '; return ostream;}↵
↵
void solveIt(){↵
int n; cin >> n;↵
vector<string> a(n);↵
for(auto &i : a) cin >> i;↵
vector<vector<int>> left(n,vector<int> (n,0)),right(n,vector<int> (n,0)),down(n,vector<int> (n,0));↵
int ans = 0;↵
for(int i=0;i<n;i++){↵
for(int j=0;j<n;j++){↵
int x = a[i][j] - '0';↵
if(left[i][j]){↵
x ^= 1;↵
if(i + 1 < n){↵
if(j - 1 >= 0) left[i + 1][j - 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
}↵
}↵
if(down[i][j]){↵
x ^= 1;↵
if(i + 1 < n) down[i + 1][j] ^= 1;↵
}↵
if(right[i][j]){↵
x ^= 1;↵
if(i + 1 < n){↵
if(j + 1 < n) right[i + 1][j + 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
}↵
}↵
if(x){↵
ans++;↵
if(i + 1 < n){↵
if(j - 1 >= 0) left[i + 1][j - 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
if(j + 1 < n) right[i + 1][j + 1] ^= 1;↵
}↵
}↵
}↵
}↵
cout << ans << '\n';↵
}↵
↵
#undef int↵
int main()↵
{↵
ios::sync_with_stdio(0);↵
cin.tie(0); cout.tie(0);↵
int tcs=1;↵
cin >> tcs;↵
for(int i=1;i<=tcs;i++){↵
solveIt();↵
}↵
}↵
```↵
</spoiler>↵
↵
↵
The first one shows TLE on testcase 8 while the second one shows accepted. Both are same solutions to the problem.↵
↵
Does anyone know why the results are so different?
↵
1.First solution
↵
<spoiler summary="My Code
```c++↵
↵
#include <bits/stdc++.h>↵
using namespace std;↵
↵
void init_code(){↵
#ifndef ONLINE_JUDGE↵
freopen("input.txt", "r", stdin);↵
freopen("output.txt", "w", stdout);↵
#endif↵
}↵
↵
↵
↵
int main() {↵
init_code();↵
// read(T);↵
int T;↵
cin>>T;↵
while(T--){↵
int n,ans = 0;↵
cin>>n;↵
vector<string>v(n);↵
for(auto&i:v){↵
cin>>i;↵
}↵
vector<vector<int>>left(n,vector<int>(n)), right(n,vector<int>(n)), down(n, vector<int>(n));↵
for(int i = 0;i<n;i++){↵
for(int j = 0;j<n;j++){↵
int x = v[i][j] - '0';↵
if(left[i][j]){↵
x^=1;↵
if(i + 1 < n){↵
if(j - 1>=0){↵
left[i + 1][j - 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
↵
}↵
}↵
if(down[i][j]){↵
x^=1;↵
if(i + 1 <n){↵
down[i + 1][j]^=1;↵
}↵
}↵
if(right[i][j]){↵
x^=1;↵
if(i + 1 < n){↵
if(j + 1 < n){↵
right[i + 1][j + 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
}↵
}↵
↵
if(x){↵
ans++;↵
if(i + 1 < n){↵
if(j - 1 >= 0){↵
left[i + 1][j - 1]^=1;↵
}↵
if(j + 1<n){↵
right[i + 1][j + 1]^=1;↵
}↵
down[i + 1][j]^=1;↵
}↵
↵
}↵
↵
}↵
↵
}↵
cout<<ans<<endl;↵
}↵
}↵
```↵
</spoiler>↵
↵
2. Second solution↵
↵
<spoiler summary="His Code">↵
```c++↵
↵
#include <bits/stdc++.h>↵
#define int long long↵
using namespace std;↵
const int mod = 998244353;↵
template <typename T>↵
istream &operator>>(istream &istream, vector<T> &v){for (auto &it : v) cin >> it; return istream;}↵
template <typename T>↵
ostream &operator<<(ostream &ostream, vector<T> &v){for (auto &it : v) cout << it << ' '; return ostream;}↵
↵
void solveIt(){↵
int n; cin >> n;↵
vector<string> a(n);↵
for(auto &i : a) cin >> i;↵
vector<vector<int>> left(n,vector<int> (n,0)),right(n,vector<int> (n,0)),down(n,vector<int> (n,0));↵
int ans = 0;↵
for(int i=0;i<n;i++){↵
for(int j=0;j<n;j++){↵
int x = a[i][j] - '0';↵
if(left[i][j]){↵
x ^= 1;↵
if(i + 1 < n){↵
if(j - 1 >= 0) left[i + 1][j - 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
}↵
}↵
if(down[i][j]){↵
x ^= 1;↵
if(i + 1 < n) down[i + 1][j] ^= 1;↵
}↵
if(right[i][j]){↵
x ^= 1;↵
if(i + 1 < n){↵
if(j + 1 < n) right[i + 1][j + 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
}↵
}↵
if(x){↵
ans++;↵
if(i + 1 < n){↵
if(j - 1 >= 0) left[i + 1][j - 1] ^= 1;↵
down[i + 1][j] ^= 1;↵
if(j + 1 < n) right[i + 1][j + 1] ^= 1;↵
}↵
}↵
}↵
}↵
cout << ans << '\n';↵
}↵
↵
#undef int↵
int main()↵
{↵
ios::sync_with_stdio(0);↵
cin.tie(0); cout.tie(0);↵
int tcs=1;↵
cin >> tcs;↵
for(int i=1;i<=tcs;i++){↵
solveIt();↵
}↵
}↵
```↵
</spoiler>↵
↵
↵
The first one shows TLE on testcase 8 while the second one shows accepted. Both are same solutions to the problem.↵
↵
Does anyone know why the results are so different?
