Submission #102924

#	Time	Username	Problem	Language	Result	Execution time	Memory
102924		bert30702	The Big Prize (IOI17_prize)	C++17	92.93 / 100	57 ms	644 KiB

prize

    #include <bits/stdc++.h>
    #include "prize.h"
    #define pii pair<int, int>
    #define F first
    #define S second
    using namespace std;
    //vector<int> ask(int p) {
    //	// cout << p << endl;
    //	int a = 0, b = 0; 
    //	int v[] = {3, 2, 3, 1, 3, 3, 2, 3};
    //	for(int i =     0; i < p; i ++) a += (v[i] < v[p]);
    //	for(int i = p + 1; i < 8; i ++) b += (v[i] < v[p]);
    //	return {a, b};
    //}
    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) {
    	// cout << l << ' ' << r << endl;
    	if(l == r) {
    		if(b.F + b.S != mx) ans.push_back({b.F + b.S, l});
    		return;
    	}
    	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 = 0;
    	for(int i = 0; i < 1000; i ++) {
    		pii tmp = query(rand() % n);
    		mx = max(mx, tmp.F + tmp.S);
    	}
    	dfs(0, n - 1, query(0), query(n - 1), mx);
    	pii mn = {mx, -1};
    	// for(auto it: ans) cout << it.S << ' '; cout << endl;
    	for(auto it: ans) mn = min(mn, it);
    	return mn.S;
    }
    //main () {
    //	cout << find_best(8);
    //}

Compilation message (stderr)

prize.cpp: In function 'void dfs(int, int, std::pair<int, int>, std::pair<int, int>, int)':
prize.cpp:29:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
      int m = l + r >> 1;
              ~~^~~

• Subtask 1: 20 / 20
• Subtask 2: 72.93 / 80