제출 #157623

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
157623		imyujin	Sparklers (JOI17_sparklers)	C++17	0 / 100	2 ms	380 KiB

sparklers

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

typedef long long lint;
typedef pair<lint, lint> pll;

#define fi first
#define se second

const int MAXN = 100010;
const int INF = 1 << 30;

lint X[MAXN];

pll solve(vector<lint> &v, vector<pll> &r) {
	pll x = pll(0, 0);
	for(auto &a : v) {
		pll t = pll(a, max(-a, 0ll));
		while(!r.empty() && t.fi < 0) {
			t.se = max(t.se, r.back().se - t.fi);
			t.fi += r.back().fi;
			r.pop_back();
		}
		if(t.fi >= 0) r.push_back(t);
		else {
			x.se = max(t.se, x.se - t.fi);
			x.fi += t.fi;
		}
	}
	return x;
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	int N, K;
	lint T;

	cin >> N >> K >> T;
	for(int i = 1; i <= N; i++) cin >> X[i];

	lint s = 0, e = INF;
	while(s < e) {
		lint m = (s + e) / 2;
		vector<lint> v1, v2;
		for(int i = 1; i < K; i++) v1.push_back(2 * T * m - X[i + 1] + X[i]);
		for(int i = N; i > K; i--) v2.push_back(2 * T * m - X[i] + X[i - 1]);
		lint sum = 0;
		vector<pll> r1, r2;
		pll x1 = solve(v1, r1);
		pll x2 = solve(v2, r2);
		/*
		printf("m = %lld\nv1 : ", m);
		for(auto a : v1) printf("%lld ", a);
		printf("\nv2 : ");
		for(auto a : v2) printf("%lld ", a);
		printf("\nr1 : ");
		for(auto a : r1) printf("(%lld, %lld) ", a.fi, a.se);
		printf("\nr2 : ");
		for(auto a : r2) printf("(%lld, %lld) ", a.fi, a.se);
		printf("\n");
		*/
		lint t = 0;
		int p1 = int(r1.size()) - 1, p2 = int(r2.size()) - 1;
		while(p1 >= 0 || p2 >= 0) {
			if(p1 >= 0 && t >= r1[p1].se) t += r1[p1--].fi;
			else if(p2 >= 0 && t >= r2[p2].se) t += r2[p2--].fi;
			else break;
		}
		if(p1 >= 0 || p2 >= 0) s = m + 1;
		else if(t >= x1.se && t >= x2.se && t >= min(x1.se - x2.fi, x2.se - x1.fi))
			e = m;
		else s = m + 1;
	}
	cout << s << "\n";
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

sparklers.cpp: In function 'int main()':
sparklers.cpp:47:8: warning: unused variable 'sum' [-Wunused-variable]
   lint sum = 0;
        ^~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50