Submission #1004329

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004329		PenguinsAreCute	Flooding Wall (BOI24_wall)	C++17	70 / 100	1853 ms	1048580 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MOD = 1e9 + 7;
const int HALF = 5e8 + 4;
struct seg {
	int s, e, m, v, lazy;
	seg *l, *r;
	seg(int _s, int _e): s(_s), e(_e), m(_s+_e>>1), v(e-s+1), lazy(1), l(NULL) {}
	void create() {
		if(!l) l=new seg(s,m), r=new seg(m+1,e);
	}
	int val() {return v*lazy%MOD;}
	void up(int x, int y, int u) {
		if(s==x&&e==y) {lazy=lazy*u%MOD; return;}
		create();
		if(y<=m) l->up(x,y,u);
		else if(x>m) r->up(x,y,u);
		else l->up(x,m,u), r->up(m+1,y,u);
		v=(l->val())+(r->val()); if(v>=MOD) v-=MOD;
	}
	void res() {
		v=e-s+1;
		lazy=1;
		if(l) l->res(), r->res();
	}
};
main() {
	int n; cin >> n;
	int a[n], b[n];
	for(int i=0;i<n;i++) cin>>a[i];
	for(int i=0;i<n;i++) cin>>b[i];
	seg sl(1,1<<30), sr(1,1<<30);
	int ansl[n], ansr[n];
	int ans = 0;
	for(int i=0;i<n;i++) {
		if(a[i]>b[i]) swap(a[i],b[i]);
		sl.up(1,a[i],0);
		sl.up(a[i]+1,b[i],HALF);
		ans-=sl.val();
	}
	sl.res();
	for(int i=n;i--;) {
		sl.up(1,a[i],0);
		sl.up(a[i]+1,b[i],HALF);
		ans-=sl.val();
	}
	for(int i=0;i<n;i++) ans-=(HALF*(a[i]+b[i]))%MOD;
	ans += (n<<30) + n * sl.val();
	ans %= MOD; if(ans<0) ans+=MOD;
	for(int i=0;i<n;i++) {ans<<=1; if(ans>=MOD) ans-=MOD;}
	cout << ans;
}

Compilation message (stderr)

Main.cpp: In constructor 'seg::seg(long long int, long long int)':
Main.cpp:9:41: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    9 |  seg(int _s, int _e): s(_s), e(_e), m(_s+_e>>1), v(e-s+1), lazy(1), l(NULL) {}
      |                                       ~~^~~
Main.cpp: At global scope:
Main.cpp:28:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   28 | main() {
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:34:6: warning: unused variable 'ansl' [-Wunused-variable]
   34 |  int ansl[n], ansr[n];
      |      ^~~~
Main.cpp:34:15: warning: unused variable 'ansr' [-Wunused-variable]
   34 |  int ansl[n], ansr[n];
      |               ^~~~

• Subtask 1: 8 / 8
• Subtask 2: 17 / 17
• Subtask 3: 19 / 19
• Subtask 4: 14 / 14
• Subtask 5: 12 / 12
• Subtask 6: 0 / 30