#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
struct Rect{
ll x,y,x2,y2;
void _minus(){
x--,y--,x2--,y2--;
}
}rect[100005];
ll n,m,pref_bl[100005],pref_wh[100005];
ll range_bl(ll l,ll r){
if(l)return pref_bl[r]-pref_bl[l-1];
return pref_bl[r];
}
ll range_wh(ll l,ll r){
if(l)return pref_wh[r]-pref_wh[l-1];
return pref_wh[r];
}
ll calc_wh(ll x,ll y,ll x2,ll y2){
ll ans=0;
ans=(x2-x+1)*(y2-y+1)-calc_bl(x,y,x2,y2);
return ans;
}
ll calc_bl(ll x,ll y,ll x2,ll y2){
ll ans=0;
ans+=range_bl(x,x2)*range_bl(y,y2);
ans+=range_wh(x,x2)*range_wh(y,y2);
return ans;
}
ll solve(ll side){
ll sz=n/side;
ll wh=0,bl=side*side*((sz*sz+1)>>1);
pref_bl[0]=1;
pref_wh[0]=0;
for(ll i=1;i<n;i++)
pref_wh[i]=pref_wh[i-1]+((i/side)&1),pref_bl[i]=i+1-pref_wh[i];
for(ll i=0;i<m;i++){
wh+=calc_wh(rect[i].x,rect[i].y,rect[i].x2,rect[i].y2);
bl-=calc_bl(rect[i].x,rect[i].y,rect[i].x2,rect[i].y2);
}
return min(wh+bl,n*n-wh-bl);
}
int main(){
scanf("%lld%lld",&n,&m);
for(ll i=0;i<m;i++)scanf("%lld%lld%lld%lld",&rect[i].x,&rect[i].y,&rect[i].x2,&rect[i].y2),rect[i]._minus();
ll res=solve(1);
for(ll i=2;i*i<=n;i++)if(n%i==0)res=min(res,min(solve(i),solve(n/i)));
printf("%lld",res);
}
Compilation message
chessboard.cpp: In function 'll calc_wh(ll, ll, ll, ll)':
chessboard.cpp:21:27: error: 'calc_bl' was not declared in this scope; did you mean 'calc_wh'?
21 | ans=(x2-x+1)*(y2-y+1)-calc_bl(x,y,x2,y2);
| ^~~~~~~
| calc_wh
chessboard.cpp: In function 'int main()':
chessboard.cpp:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
44 | scanf("%lld%lld",&n,&m);
| ~~~~~^~~~~~~~~~~~~~~~~~
chessboard.cpp:45:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
45 | for(ll i=0;i<m;i++)scanf("%lld%lld%lld%lld",&rect[i].x,&rect[i].y,&rect[i].x2,&rect[i].y2),rect[i]._minus();
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
