Submission #51017

#	Time	Username	Problem	Language	Result	Execution time	Memory
51017		FLDutchman	The Big Prize (IOI17_prize)	C++14	100 / 100	68 ms	2236 KiB

prize

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

#define mp make_pair
#define pb push_back
const int INF = 1000000000;

typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long double num;
typedef pair<num, num> nn;
typedef vector<nn> vnn;
typedef vector<num> vn;
typedef vector<vn> vvn;

vii answers;
int maxVal = 0;
int N;

ii query(int i){
    if(answers[i] != mp(-1, -1)) return answers[i];
    vi a = ask(i);
    //cerr << a[0] << " " << a[1] << endl;
    return answers[i] = mp(a[0], a[1]);
}


void genQueries(){
    // do 711 queries in the shape of a bs
    queue<ii> bounds;
    bounds.push(mp(-1, N));
    int queriesLeft = 711;
    while(queriesLeft --){
        ii q = bounds.front(); bounds.pop();
        int mb = (q.first+q.second)/2;
        query(mb);
        maxVal = max(maxVal, answers[mb].first + answers[mb].second);
        bounds.push(mp(q.first, mb));
        bounds.push(mp(mb, q.second));
    }
}

int find_best(int n){
    N = n;
    answers.assign(n, mp(-1, -1));
    genQueries();
    int betterFound = 0;
    int lb = -1;
    int lastLb = -1;

    while(betterFound < maxVal){
        int rb =  n;
        int lb = -1;
        while(lb + 1 != rb){
            int mb = (lb + rb)/2;
            ii ans = query(mb);
            if(ans.second >= maxVal - betterFound or mb <= lastLb){
                lb = mb;
            } else {
                rb = mb;
            }
        }
        //cerr << rb << endl;
        betterFound++;
        lb++;
        lastLb = lb;
    }

    for(int i = 0; i < answers.size(); i++){
        if(answers[i] == mp(0, 0)) return i;
    }

}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:73:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < answers.size(); i++){
                    ~~^~~~~~~~~~~~~~~~
prize.cpp:52:9: warning: unused variable 'lb' [-Wunused-variable]
     int lb = -1;
         ^~
prize.cpp:77:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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