Submission #408569

#	Time	Username	Problem	Language	Result	Execution time	Memory
408569		Kevin_Zhang_TW	The Big Prize (IOI17_prize)	C++17	90 / 100	73 ms	7620 KiB

prize

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
 
#include "prize.h"
 
const int MAX_N = 300010;
 
vector<int> qry(int id) {
	static vector<int> mem[MAX_N];
	if (mem[id].size()) return mem[id];
	return mem[id] = ask(id);
}
 
int sum(int id) {
	return qry(id)[0] + qry(id)[1];
}
 
int find_best(int n) {
 
	int cnt = 1, m, h;
 
	while (h < n) {
		while (sum(h) < cnt) {
			if (sum(h) == 0) return h;
			++h;
		}
		cnt = sum(h);
		assert(cnt < 500);
		int r = min(n-1, h + (1<<5));

		if (sum(r) != cnt || qry(r)[0] != qry(h)[0]) {
			++h;
			continue;
		}
 
		int l = h;
		for (int j = 1<<9;j > 0;j >>= 1) {
			if (l + j >= n) continue;
			int m = l + j;
			if (sum(m) > cnt) {
				cnt = sum(m);
				break;
			}
			if (sum(m) == cnt && qry(m)[0] == qry(h)[0])
				l = m;
		}
		if (sum(h) != cnt) continue;
		h = l + 1;
	}
	assert(false);
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:35:15: warning: unused variable 'm' [-Wunused-variable]
   35 |  int cnt = 1, m, h;
      |               ^
prize.cpp:39:28: warning: 'h' may be used uninitialized in this function [-Wmaybe-uninitialized]
   39 |    if (sum(h) == 0) return h;
      |                            ^

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80