Submission #103164

#	Time	Username	Problem	Language	Result	Execution time	Memory
103164		bert30702	The Big Prize (IOI17_prize)	C++17	100 / 100	58 ms	636 KiB

prize

#include <bits/stdc++.h>
#include "prize.h"
#define pii pair<int, int>
#define F first
#define S second
using namespace std;
unordered_map<int, pii> mp;
pii query(int p) {
	if(mp.find(p) != mp.end()) return mp[p];
	vector<int> v = ask(p);
	return mp[p] = {v[0], v[1]};
}
vector<pii> ans;
void dfs(int l, int r, pii a, pii b, int mx) {
	if(l == r) return ans.push_back({b.F + b.S, l});
	if(a == b) return;
	int m = l + r >> 1;
	pii v = query(m);
	if(v.F + v.S != mx) {
		ans.push_back({v.F + v.S, m});
		if(m != l) dfs(l, m - 1, a, query(m - 1), mx);
		if(m != r) dfs(m + 1, r, query(m + 1), b, mx);
	}
	else {
		if(v == a) return dfs(m + 1, r, v, b, mx);
		if(v == b) return dfs(    l, m, a, v, mx);
		dfs(    l, m, a, v, mx);
		dfs(m + 1, r, v, b, mx);
	}
}
int find_best(int n) {
	srand(time(0));
	int mx = query(0).F + query(0).S;
	if(mx == 0) return 0;
	dfs(0, n - 1, query(0), query(n - 1), mx);
	for(auto it: ans) if(it.F == 0) return it.S;
}

Compilation message (stderr)

prize.cpp: In function 'void dfs(int, int, std::pair<int, int>, std::pair<int, int>, int)':
prize.cpp:17:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int m = l + r >> 1;
          ~~^~~
prize.cpp: In function 'int find_best(int)':
prize.cpp:37:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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