Submission #677965

#	Time	Username	Problem	Language	Result	Execution time	Memory
677965		arnold518	Remittance (JOI19_remittance)	C++17	100 / 100	208 ms	23816 KiB

remittance

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e6;

int N;
ll A[MAXN+10], B[MAXN+10], X[MAXN+10], S;

bool solve(ll X)
{
	ll t=X;
	for(int i=N; i>=1; i--)
	{
		X=X*2+B[i]-A[i];
		if(X<0) return true;
		if(X>-S) return false;
	}
	return X<=t;
}

int main()
{
	scanf("%d", &N);
	for(int i=1; i<=N; i++) scanf("%lld%lld", &A[i], &B[i]), S+=B[i]-A[i];

	if(S>0) return !printf("No\n");
	ll lo=0, hi=-S+1;
	while(lo+1<hi)
	{
		ll mid=lo+hi>>1;
		if(solve(mid)) lo=mid;
		else hi=mid;
	}
	
	ll t=lo, x=lo;
	for(int i=N; i>=1; i--)
	{
		x=x*2+B[i]-A[i];
		if(x<0) return !printf("No\n");
		if(x>-S) return !printf("No\n");
		X[i]=x;
	}
	if(x!=t) return !printf("No\n");
	for(int i=1; i<=N; i++) if(X[i]==0) return !printf("Yes\n");

	bool flag=false;
	for(int i=1; i<=N; i++) if(B[i]!=0) flag=true;
	if(!flag) return !printf("No\n");

	return !printf("Yes\n");

}

Compilation message (stderr)

remittance.cpp: In function 'int main()':
remittance.cpp:34:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   34 |   ll mid=lo+hi>>1;
      |          ~~^~~
remittance.cpp:27:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |  scanf("%d", &N);
      |  ~~~~~^~~~~~~~~~
remittance.cpp:28:31: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |  for(int i=1; i<=N; i++) scanf("%lld%lld", &A[i], &B[i]), S+=B[i]-A[i];
      |                          ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 45 / 45